{"transactions":[{"id":488,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2026-09-02T20:15:29.000Z","date":"2026-08-28","kind":"grant","planned":false,"acquired":true,"shares":37,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents dividend equivalents earned on the prior RSU grant awards."}],"balance_after":15770,"source":{"system":"sec-edgar","filing":"0001635271-26-000005","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1635271/000163527126000005/primarydocument.xml","form_type":"4"}},{"id":756137,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2026-06-02T20:06:35.000Z","date":"2026-05-29","kind":"grant","planned":false,"acquired":true,"shares":32,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents dividend equivalents earned on the prior RSU grant awards."}],"balance_after":15733,"source":{"system":"sec-edgar","filing":"0001635271-26-000004","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/792987/000163527126000004/primarydocument.xml","form_type":"4"}},{"id":821728,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2026-04-02T20:57:29.000Z","date":"2026-03-31","kind":"grant","planned":false,"acquired":true,"shares":31,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents dividend equivalents earned on the prior RSU grant awards."}],"balance_after":15701,"source":{"system":"sec-edgar","filing":"0001635271-26-000003","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/792987/000163527126000003/primarydocument.xml","form_type":"4"}},{"id":875776,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2026-03-03T01:50:41.000Z","date":"2026-02-26","kind":"tax_withholding","planned":false,"acquired":false,"shares":535,"price":61.31,"value":32800.85,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Shares withheld to satisfy applicable tax withholding obligation."}],"balance_after":15670,"source":{"system":"sec-edgar","filing":"0001635271-26-000002","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/792987/000163527126000002/primarydocument.xml","form_type":"4"}},{"id":886626,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2026-02-24T17:54:40.000Z","date":"2026-02-20","kind":"grant","planned":false,"acquired":true,"shares":5362,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F2","text":"Reported transaction is an annual grant of RSUs under the Company's 2025 Equity Incentive Plan."}],"balance_after":16205,"source":{"system":"sec-edgar","filing":"0001635271-26-000001","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/792987/000163527126000001/primarydocument.xml","form_type":"4"}},{"id":886625,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2026-02-24T17:54:40.000Z","date":"2026-02-20","kind":"tax_withholding","planned":false,"acquired":false,"shares":1191,"price":57.44,"value":68411.04,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Shares withheld to satisfy applicable tax withholding obligation."}],"balance_after":10843,"source":{"system":"sec-edgar","filing":"0001635271-26-000001","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/792987/000163527126000001/primarydocument.xml","form_type":"4"}},{"id":985855,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2025-12-01T21:13:48.000Z","date":"2025-11-26","kind":"grant","planned":false,"acquired":true,"shares":33,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents dividend equivalents earned on the prior RSU grant awards."}],"balance_after":12034,"source":{"system":"sec-edgar","filing":"0001635271-25-000004","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/792987/000163527125000004/primarydocument.xml","form_type":"4"}},{"id":1050783,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2025-09-03T20:09:23.000Z","date":"2025-08-29","kind":"grant","planned":false,"acquired":true,"shares":31,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents dividend equivalents earned on the prior RSU grant awards."}],"balance_after":12001,"source":{"system":"sec-edgar","filing":"0001635271-25-000003","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/792987/000163527125000003/primarydocument.xml","form_type":"4"}},{"id":1126588,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2025-06-03T21:26:57.000Z","date":"2025-05-30","kind":"grant","planned":false,"acquired":true,"shares":37,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents dividend equivalents earned on the prior RSU grant awards."}],"balance_after":11970,"source":{"system":"sec-edgar","filing":"0001562180-25-004379","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/792987/000156218025004379/primarydocument.xml","form_type":"4"}},{"id":1188509,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2025-03-31T21:45:41.000Z","date":"2025-03-31","kind":"grant","planned":false,"acquired":true,"shares":41,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents dividend equivalents earned on the prior RSU grant awards."}],"balance_after":11933,"source":{"system":"sec-edgar","filing":"0001562180-25-002811","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/792987/000156218025002811/primarydocument.xml","form_type":"4"}},{"id":1239705,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2025-02-28T20:59:18.000Z","date":"2025-02-26","kind":"tax_withholding","planned":false,"acquired":false,"shares":611,"price":31.17,"value":19044.87,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Shares withheld to satisfy applicable tax withholding obligation."}],"balance_after":11892,"source":{"system":"sec-edgar","filing":"0001562180-25-001781","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/792987/000156218025001781/primarydocument.xml","form_type":"4"}},{"id":1251310,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2025-02-24T21:29:58.000Z","date":"2025-02-20","kind":"grant","planned":false,"acquired":true,"shares":8358,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Reported transaction is an annual grant of RSUs under the Company's 2021 Equity Incentive Plan."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Amount corrected from previous filing"}],"balance_after":12503,"source":{"system":"sec-edgar","filing":"0001562180-25-001533","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/792987/000156218025001533/primarydocument.xml","form_type":"4"}},{"id":1362789,"issuer":{"id":425,"kind":"organization","name":"ASTEC INDUSTRIES INC","symbol":"ASTE"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Financial Officer"}}],"security":"Common Stock","published_at":"2024-11-18T21:27:50.000Z","date":"2024-11-15","kind":"grant","planned":false,"acquired":true,"shares":8290,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Reported transaction is an annual grant of RSUs under the Company's 2021 Equity Incentive Plan."}],"balance_after":8290,"source":{"system":"sec-edgar","filing":"0001562180-24-007741","document":"primarydocument.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/792987/000156218024007741/primarydocument.xml","form_type":"4"}},{"id":1983614,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2023-03-01T17:40:00.000Z","date":"2023-02-28","kind":"exercise","acquired":false,"shares":4785,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F5","text":"Each restricted stock unit represents a contingent right to receive one share of Class A common stock of the Issuer (\"Class A Common Stock\"). The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's Human Capital and Compensation Committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F8","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2023."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F8","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2023."}],"balance_after":9568,"derivative":{"underlying":"Class A Common Stock","underlying_shares":4785},"source":{"system":"sec-edgar","filing":"0001628280-23-005896","document":"wf-form4_167771037900479.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":8,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828023005896/wf-form4_167771037900479.xml","form_type":"4"}},{"id":1983613,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2023-03-01T17:40:00.000Z","date":"2023-02-28","kind":"exercise","acquired":false,"shares":5595,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F5","text":"Each restricted stock unit represents a contingent right to receive one share of Class A common stock of the Issuer (\"Class A Common Stock\"). The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's Human Capital and Compensation Committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F7","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2022."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F7","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2022."}],"balance_after":5595,"derivative":{"underlying":"Class A Common Stock","underlying_shares":5595},"source":{"system":"sec-edgar","filing":"0001628280-23-005896","document":"wf-form4_167771037900479.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828023005896/wf-form4_167771037900479.xml","form_type":"4"}},{"id":1983612,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2023-03-01T17:40:00.000Z","date":"2023-02-28","kind":"exercise","acquired":false,"shares":6636,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F5","text":"Each restricted stock unit represents a contingent right to receive one share of Class A common stock of the Issuer (\"Class A Common Stock\"). The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's Human Capital and Compensation Committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F6","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2021."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F6","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2021."}],"balance_after":0,"derivative":{"underlying":"Class A Common Stock","underlying_shares":6636},"source":{"system":"sec-edgar","filing":"0001628280-23-005896","document":"wf-form4_167771037900479.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828023005896/wf-form4_167771037900479.xml","form_type":"4"}},{"id":1983611,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2023-03-01T17:40:00.000Z","date":"2023-02-28","kind":"tax_withholding","acquired":false,"shares":10433,"price":29.54,"value":308190.82,"ownership":{"direct":true},"balance_after":220418,"source":{"system":"sec-edgar","filing":"0001628280-23-005896","document":"wf-form4_167771037900479.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828023005896/wf-form4_167771037900479.xml","form_type":"4"}},{"id":1983610,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2023-03-01T17:40:00.000Z","date":"2023-02-28","kind":"grant","acquired":true,"shares":18298,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F4","text":"Reflects shares of Class A Common Stock earned and delivered on performance units previously granted based upon the satisfaction of certain performance criteria."}],"balance_after":230851,"source":{"system":"sec-edgar","filing":"0001628280-23-005896","document":"wf-form4_167771037900479.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828023005896/wf-form4_167771037900479.xml","form_type":"4"}},{"id":1983609,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2023-03-01T17:40:00.000Z","date":"2023-02-28","kind":"exercise","acquired":true,"shares":4785,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":212553,"source":{"system":"sec-edgar","filing":"0001628280-23-005896","document":"wf-form4_167771037900479.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828023005896/wf-form4_167771037900479.xml","form_type":"4"}},{"id":1983608,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2023-03-01T17:40:00.000Z","date":"2023-02-28","kind":"exercise","acquired":true,"shares":5595,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":207768,"source":{"system":"sec-edgar","filing":"0001628280-23-005896","document":"wf-form4_167771037900479.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828023005896/wf-form4_167771037900479.xml","form_type":"4"}},{"id":1983607,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2023-03-01T17:40:00.000Z","date":"2023-02-28","kind":"exercise","acquired":true,"shares":6635,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Total holdings include shares of Class A Common Stock received pursuant to a stock dividend paid on December 29, 2022."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F3","text":"Total holdings include shares of Class A Common Stock acquired through the Issuer's Employee Stock Purchase Plan on April 14, 2022 and October 18, 2022."}],"balance_after":202173,"source":{"system":"sec-edgar","filing":"0001628280-23-005896","document":"wf-form4_167771037900479.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828023005896/wf-form4_167771037900479.xml","form_type":"4"}},{"id":2199032,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2022-08-01T18:25:21.000Z","date":"2022-07-30","kind":"exercise","acquired":false,"shares":13328,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's Human Capital and Compensation Committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The Reporting Person was granted 26,656 restricted stock units that vest in two equal installments beginning on July 30, 2021."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The Reporting Person was granted 26,656 restricted stock units that vest in two equal installments beginning on July 30, 2021."}],"balance_after":0,"derivative":{"underlying":"Class A Common Stock","underlying_shares":13328},"source":{"system":"sec-edgar","filing":"0001628280-22-019986","document":"wf-form4_165939270276640.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022019986/wf-form4_165939270276640.xml","form_type":"4"}},{"id":2199031,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2022-08-01T18:25:21.000Z","date":"2022-07-30","kind":"tax_withholding","acquired":false,"shares":5851,"price":27.51,"value":160961.01,"ownership":{"direct":true},"balance_after":191968,"source":{"system":"sec-edgar","filing":"0001628280-22-019986","document":"wf-form4_165939270276640.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022019986/wf-form4_165939270276640.xml","form_type":"4"}},{"id":2199030,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2022-08-01T18:25:21.000Z","date":"2022-07-30","kind":"exercise","acquired":true,"shares":13328,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Includes 648 shares acquired through the Issuer's Employee Stock Purchase Plan on April 14, 2022."}],"balance_after":197819,"source":{"system":"sec-edgar","filing":"0001628280-22-019986","document":"wf-form4_165939270276640.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022019986/wf-form4_165939270276640.xml","form_type":"4"}},{"id":2354304,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2022-03-03T16:20:15.000Z","date":"2022-03-01","kind":"grant","acquired":true,"shares":14353,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each restricted stock unit represents a contingent right to receive one share of Class A common stock of the Issuer (\"Class A Common Stock\"). The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's Human Capital and Compensation Committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2023."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2023."}],"balance_after":14353,"derivative":{"underlying":"Class A Common Stock","underlying_shares":14353},"source":{"system":"sec-edgar","filing":"0001628280-22-004918","document":"wf-form4_164634238386654.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022004918/wf-form4_164634238386654.xml","form_type":"4"}},{"id":2365336,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2022-03-01T17:53:38.000Z","date":"2022-02-28","kind":"exercise","acquired":false,"shares":5596,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's Human Capital and Compensation Committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F6","text":"The Reporting Person was granted 16,786 restricted stock units that vest in three equal annual installments beginning on February 28, 2022."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F6","text":"The Reporting Person was granted 16,786 restricted stock units that vest in three equal annual installments beginning on February 28, 2022."}],"balance_after":11190,"derivative":{"underlying":"Class A Common Stock","underlying_shares":5596},"source":{"system":"sec-edgar","filing":"0001628280-22-004585","document":"wf-form4_164617518743778.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":8,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022004585/wf-form4_164617518743778.xml","form_type":"4"}},{"id":2365335,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2022-03-01T17:53:38.000Z","date":"2022-02-28","kind":"exercise","acquired":false,"shares":6635,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's Human Capital and Compensation Committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"The Reporting Person was granted 19,905 restricted stock units that vest in three equal annual installments beginning on February 28, 2021."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"The Reporting Person was granted 19,905 restricted stock units that vest in three equal annual installments beginning on February 28, 2021."}],"balance_after":13270,"derivative":{"underlying":"Class A Common Stock","underlying_shares":6635},"source":{"system":"sec-edgar","filing":"0001628280-22-004585","document":"wf-form4_164617518743778.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022004585/wf-form4_164617518743778.xml","form_type":"4"}},{"id":2365334,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2022-03-01T17:53:38.000Z","date":"2022-02-28","kind":"exercise","acquired":false,"shares":9820,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's Human Capital and Compensation Committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The Reporting Person was granted 29,460 restricted stock units that vest in three equal annual installments beginning on February 28, 2020."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"The Reporting Person was granted 29,460 restricted stock units that vest in three equal annual installments beginning on February 28, 2020."}],"balance_after":19640,"derivative":{"underlying":"Class A Common Stock","underlying_shares":9820},"source":{"system":"sec-edgar","filing":"0001628280-22-004585","document":"wf-form4_164617518743778.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022004585/wf-form4_164617518743778.xml","form_type":"4"}},{"id":2365333,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2022-03-01T17:53:38.000Z","date":"2022-02-28","kind":"tax_withholding","acquired":false,"shares":27122,"price":31.22,"value":846748.84,"ownership":{"direct":true},"balance_after":183843,"source":{"system":"sec-edgar","filing":"0001628280-22-004585","document":"wf-form4_164617518743778.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022004585/wf-form4_164617518743778.xml","form_type":"4"}},{"id":2365332,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2022-03-01T17:53:38.000Z","date":"2022-02-28","kind":"grant","acquired":true,"shares":58920,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F2","text":"Reflects shares of Class A Common Stock earned and delivered on performance units previously granted based upon the satisfaction of certain performance criteria."}],"balance_after":210965,"source":{"system":"sec-edgar","filing":"0001628280-22-004585","document":"wf-form4_164617518743778.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022004585/wf-form4_164617518743778.xml","form_type":"4"}},{"id":2365331,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2022-03-01T17:53:38.000Z","date":"2022-02-28","kind":"exercise","acquired":true,"shares":5596,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":152045,"source":{"system":"sec-edgar","filing":"0001628280-22-004585","document":"wf-form4_164617518743778.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022004585/wf-form4_164617518743778.xml","form_type":"4"}},{"id":2365330,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2022-03-01T17:53:38.000Z","date":"2022-02-28","kind":"exercise","acquired":true,"shares":6635,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":146449,"source":{"system":"sec-edgar","filing":"0001628280-22-004585","document":"wf-form4_164617518743778.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022004585/wf-form4_164617518743778.xml","form_type":"4"}},{"id":2365329,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2022-03-01T17:53:38.000Z","date":"2022-02-28","kind":"exercise","acquired":true,"shares":9820,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":139814,"source":{"system":"sec-edgar","filing":"0001628280-22-004585","document":"wf-form4_164617518743778.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000162828022004585/wf-form4_164617518743778.xml","form_type":"4"}},{"id":2617736,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2021-08-03T17:05:53.000Z","date":"2021-07-30","kind":"exercise","acquired":false,"shares":13328,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock. The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The Reporting Person was granted 26,656 restricted stock units that vest in two equal annual installments beginning on July 30, 2021."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F3","text":"The Reporting Person was granted 26,656 restricted stock units that vest in two equal annual installments beginning on July 30, 2021."}],"balance_after":13328,"derivative":{"underlying":"Class A Common Stock","underlying_shares":13328},"source":{"system":"sec-edgar","filing":"0001104659-21-099524","document":"tm2123895-3_4seq1.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465921099524/tm2123895-3_4seq1.xml","form_type":"4"}},{"id":2617735,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2021-08-03T17:05:53.000Z","date":"2021-07-30","kind":"tax_withholding","acquired":false,"shares":3246,"price":33.6,"value":109065.6,"ownership":{"direct":true},"balance_after":129994,"source":{"system":"sec-edgar","filing":"0001104659-21-099524","document":"tm2123895-3_4seq1.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465921099524/tm2123895-3_4seq1.xml","form_type":"4"}},{"id":2617734,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2021-08-03T17:05:53.000Z","date":"2021-07-30","kind":"exercise","acquired":true,"shares":13328,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":133240,"source":{"system":"sec-edgar","filing":"0001104659-21-099524","document":"tm2123895-3_4seq1.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465921099524/tm2123895-3_4seq1.xml","form_type":"4"}},{"id":2764215,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2021-04-01T21:20:06.000Z","date":"2021-03-30","kind":"grant","acquired":true,"shares":16786,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each restricted stock unit represents a contingent right to receive one share of Class A common stock of the Issuer (\"Class A Common Stock\"). The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2022."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2022."}],"balance_after":16786,"derivative":{"underlying":"Class A Common Stock","underlying_shares":16786},"source":{"system":"sec-edgar","filing":"0001104659-21-045789","document":"tm2111872-4_4seq1.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465921045789/tm2111872-4_4seq1.xml","form_type":"4"}},{"id":2820108,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2021-03-02T19:25:48.000Z","date":"2021-02-28","kind":"exercise","acquired":false,"shares":6635,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"On February 28, 2020, the Reporting Person was granted 19,905 restricted stock units that vest in three equal annual installments beginning on February 28, 2021."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"On February 28, 2020, the Reporting Person was granted 19,905 restricted stock units that vest in three equal annual installments beginning on February 28, 2021."}],"balance_after":13270,"derivative":{"underlying":"Class A Common Stock","underlying_shares":6635},"source":{"system":"sec-edgar","filing":"0001104659-21-030929","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465921030929/a4.xml","form_type":"4"}},{"id":2820107,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2021-03-02T19:25:48.000Z","date":"2021-02-28","kind":"exercise","acquired":false,"shares":9820,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"On February 28, 2019, the Reporting Person was granted 29,460 restricted stock units that vest in three equal annual installments beginning on February 28, 2020."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"On February 28, 2019, the Reporting Person was granted 29,460 restricted stock units that vest in three equal annual installments beginning on February 28, 2020."}],"balance_after":9820,"derivative":{"underlying":"Class A Common Stock","underlying_shares":9820},"source":{"system":"sec-edgar","filing":"0001104659-21-030929","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465921030929/a4.xml","form_type":"4"}},{"id":2820106,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2021-03-02T19:25:48.000Z","date":"2021-02-28","kind":"exercise","acquired":false,"shares":4676,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"On February 28, 2018, the Reporting Person was granted 14,027 restricted stock units that vest in three equal annual installments beginning on February 28, 2019."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F3","text":"On February 28, 2018, the Reporting Person was granted 14,027 restricted stock units that vest in three equal annual installments beginning on February 28, 2019."}],"balance_after":0,"derivative":{"underlying":"Class A Common Stock","underlying_shares":4676},"source":{"system":"sec-edgar","filing":"0001104659-21-030929","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465921030929/a4.xml","form_type":"4"}},{"id":2820105,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2021-03-02T19:25:48.000Z","date":"2021-02-28","kind":"tax_withholding","acquired":false,"shares":6169,"price":27.71,"value":170942.99,"ownership":{"direct":true},"balance_after":119912,"source":{"system":"sec-edgar","filing":"0001104659-21-030929","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465921030929/a4.xml","form_type":"4"}},{"id":2820104,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2021-03-02T19:25:48.000Z","date":"2021-02-28","kind":"exercise","acquired":true,"shares":6635,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":126081,"source":{"system":"sec-edgar","filing":"0001104659-21-030929","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465921030929/a4.xml","form_type":"4"}},{"id":2820103,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2021-03-02T19:25:48.000Z","date":"2021-02-28","kind":"exercise","acquired":true,"shares":9820,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":119446,"source":{"system":"sec-edgar","filing":"0001104659-21-030929","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465921030929/a4.xml","form_type":"4"}},{"id":2820102,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2021-03-02T19:25:48.000Z","date":"2021-02-28","kind":"exercise","acquired":true,"shares":4676,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":109626,"source":{"system":"sec-edgar","filing":"0001104659-21-030929","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465921030929/a4.xml","form_type":"4"}},{"id":3071351,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2020-08-03T19:25:46.000Z","date":"2020-07-30","kind":"grant","acquired":true,"shares":26656,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each restricted stock unit represents a contingent right to receive one share of Class A common stock of the Issuer (\"Class A Common Stock\").  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"These restricted stock units vest in two equal annual installments beginning on July 30, 2021."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"These restricted stock units vest in two equal annual installments beginning on July 30, 2021."}],"balance_after":26656,"derivative":{"underlying":"Class A Common Stock","underlying_shares":26656},"source":{"system":"sec-edgar","filing":"0001104659-20-089750","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465920089750/a4.xml","form_type":"4"}},{"id":3232442,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2020-03-03T21:46:48.000Z","date":"2020-02-28","kind":"grant","acquired":true,"shares":19905,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F7","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2021."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F7","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2021."}],"balance_after":19905,"derivative":{"underlying":"Class A Common Stock","underlying_shares":19905},"source":{"system":"sec-edgar","filing":"0001104659-20-028867","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":9,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465920028867/a4.xml","form_type":"4"}},{"id":3232441,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2020-03-03T21:46:48.000Z","date":"2020-02-28","kind":"exercise","acquired":false,"shares":9820,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F6","text":"On February 28, 2019, the Reporting Person was granted 29,460 restricted stock units that vest in three equal annual installments beginning on February 28, 2020."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F6","text":"On February 28, 2019, the Reporting Person was granted 29,460 restricted stock units that vest in three equal annual installments beginning on February 28, 2020."}],"balance_after":19640,"derivative":{"underlying":"Class A Common Stock","underlying_shares":9820},"source":{"system":"sec-edgar","filing":"0001104659-20-028867","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":8,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465920028867/a4.xml","form_type":"4"}},{"id":3232440,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2020-03-03T21:46:48.000Z","date":"2020-02-28","kind":"exercise","acquired":false,"shares":4676,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"On February 28, 2018, the Reporting Person was granted 14,027 restricted stock units that vest in three equal annual installments beginning on February 28, 2019."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"On February 28, 2018, the Reporting Person was granted 14,027 restricted stock units that vest in three equal annual installments beginning on February 28, 2019."}],"balance_after":4676,"derivative":{"underlying":"Class A Common Stock","underlying_shares":4676},"source":{"system":"sec-edgar","filing":"0001104659-20-028867","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465920028867/a4.xml","form_type":"4"}},{"id":3232439,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2020-03-03T21:46:48.000Z","date":"2020-02-28","kind":"exercise","acquired":false,"shares":3843,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"On February 28, 2017, the Reporting Person was granted 11,530 restricted stock units that vest in three equal annual installments beginning on February 28, 2018."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"On February 28, 2017, the Reporting Person was granted 11,530 restricted stock units that vest in three equal annual installments beginning on February 28, 2018."}],"balance_after":0,"derivative":{"underlying":"Class A Common Stock","underlying_shares":3843},"source":{"system":"sec-edgar","filing":"0001104659-20-028867","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465920028867/a4.xml","form_type":"4"}},{"id":3232438,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2020-03-03T21:46:48.000Z","date":"2020-02-28","kind":"tax_withholding","acquired":false,"shares":7663,"price":19.54,"value":149735.02,"ownership":{"direct":true},"balance_after":104950,"source":{"system":"sec-edgar","filing":"0001104659-20-028867","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465920028867/a4.xml","form_type":"4"}},{"id":3232437,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2020-03-03T21:46:48.000Z","date":"2020-02-28","kind":"grant","acquired":true,"shares":7808,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F2","text":"Reflects shares of Class A Common Stock earned and delivered on performance units previously granted based upon the satisfaction of certain performance criteria."}],"balance_after":112613,"source":{"system":"sec-edgar","filing":"0001104659-20-028867","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465920028867/a4.xml","form_type":"4"}},{"id":3232436,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2020-03-03T21:46:48.000Z","date":"2020-02-28","kind":"exercise","acquired":true,"shares":9820,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":104805,"source":{"system":"sec-edgar","filing":"0001104659-20-028867","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465920028867/a4.xml","form_type":"4"}},{"id":3232435,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2020-03-03T21:46:48.000Z","date":"2020-02-28","kind":"exercise","acquired":true,"shares":4676,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":94985,"source":{"system":"sec-edgar","filing":"0001104659-20-028867","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465920028867/a4.xml","form_type":"4"}},{"id":3232434,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2020-03-03T21:46:48.000Z","date":"2020-02-28","kind":"exercise","acquired":true,"shares":3843,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":90309,"source":{"system":"sec-edgar","filing":"0001104659-20-028867","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465920028867/a4.xml","form_type":"4"}},{"id":3363038,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Options (right to buy)","published_at":"2019-11-21T19:26:06.000Z","date":"2019-11-20","kind":"exercise","acquired":false,"shares":28395,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F6","text":"Reflects the grant of 28,395 options that vested in three equal annual installments beginning on February 24, 2017."}],"balance_after":0,"derivative":{"exercise_price":17.07,"expiration_date":"2026-02-24","underlying":"Class A Common Stock","underlying_shares":28395},"source":{"system":"sec-edgar","filing":"0001104659-19-066338","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":8,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919066338/a4.xml","form_type":"4"}},{"id":3363037,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Options (right to buy)","published_at":"2019-11-21T19:26:06.000Z","date":"2019-11-20","kind":"exercise","acquired":false,"shares":131560,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"Reflects the grant of 131,560 options that vested in four equal annual installments beginning on March 11, 2016."}],"balance_after":0,"derivative":{"exercise_price":18,"expiration_date":"2025-03-11","underlying":"Class A Common Stock","underlying_shares":131560},"source":{"system":"sec-edgar","filing":"0001104659-19-066338","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919066338/a4.xml","form_type":"4"}},{"id":3363036,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Options (right to buy)","published_at":"2019-11-21T19:26:06.000Z","date":"2019-11-20","kind":"exercise","acquired":false,"shares":101200,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"Reflects the grant of 101,200 options that vested in four equal annual installments beginning on March 11, 2016."}],"balance_after":0,"derivative":{"exercise_price":18,"expiration_date":"2025-03-11","underlying":"Class A Common Stock","underlying_shares":101200},"source":{"system":"sec-edgar","filing":"0001104659-19-066338","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919066338/a4.xml","form_type":"4"}},{"id":3363035,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2019-11-21T19:26:06.000Z","date":"2019-11-20","kind":"sale","acquired":true,"shares":261155,"price":24.14,"value":6304281.7,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $24.10 to $24.26, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above."}],"balance_after":86466,"source":{"system":"sec-edgar","filing":"0001104659-19-066338","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919066338/a4.xml","form_type":"4"}},{"id":3363034,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2019-11-21T19:26:06.000Z","date":"2019-11-20","kind":"exercise","acquired":true,"shares":28395,"price":17.07,"value":484702.65,"ownership":{"direct":true},"balance_after":347621,"source":{"system":"sec-edgar","filing":"0001104659-19-066338","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919066338/a4.xml","form_type":"4"}},{"id":3363033,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2019-11-21T19:26:06.000Z","date":"2019-11-20","kind":"exercise","acquired":true,"shares":131560,"price":18,"value":2368080.0,"ownership":{"direct":true},"balance_after":319226,"source":{"system":"sec-edgar","filing":"0001104659-19-066338","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919066338/a4.xml","form_type":"4"}},{"id":3363032,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2019-11-21T19:26:06.000Z","date":"2019-11-20","kind":"exercise","acquired":true,"shares":101200,"price":18,"value":1821600.0,"ownership":{"direct":true},"balance_after":187666,"source":{"system":"sec-edgar","filing":"0001104659-19-066338","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919066338/a4.xml","form_type":"4"}},{"id":3363031,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2019-11-21T19:26:06.000Z","date":"2019-11-19","kind":"sale","acquired":false,"shares":30000,"price":23.75,"value":712500.0,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $23.75 to $23.77, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Reflects securities held by trusts for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee."}],"balance_after":0,"source":{"system":"sec-edgar","filing":"0001104659-19-066338","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919066338/a4.xml","form_type":"4"}},{"id":3378851,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2019-11-06T17:01:28.000Z","date":"2019-11-04","kind":"sale","acquired":false,"shares":30000,"price":23.6,"value":708000.0,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $23.44 to $23.75, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Reflects securities held by trusts for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee."}],"balance_after":30000,"source":{"system":"sec-edgar","filing":"0001104659-19-060569","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919060569/a4.xml","form_type":"4"}},{"id":3619049,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2019-03-04T20:01:56.000Z","date":"2019-02-28","kind":"grant","acquired":true,"shares":29460,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F6","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2020."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F6","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2020."}],"balance_after":29460,"derivative":{"underlying":"Class A Common Stock","underlying_shares":29460},"source":{"system":"sec-edgar","filing":"0001104659-19-012633","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919012633/a4.xml","form_type":"4"}},{"id":3619048,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2019-03-04T20:01:56.000Z","date":"2019-02-28","kind":"exercise","acquired":false,"shares":4675,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"On February 28, 2018, the Reporting Person was granted 14,027 restricted stock units that vest in three equal annual installments beginning on February 28, 2019."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"On February 28, 2018, the Reporting Person was granted 14,027 restricted stock units that vest in three equal annual installments beginning on February 28, 2019."}],"balance_after":9352,"derivative":{"underlying":"Class A Common Stock","underlying_shares":4675},"source":{"system":"sec-edgar","filing":"0001104659-19-012633","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919012633/a4.xml","form_type":"4"}},{"id":3619047,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2019-03-04T20:01:56.000Z","date":"2019-02-28","kind":"exercise","acquired":false,"shares":3843,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"On February 28, 2017, the Reporting Person was granted 11,530 restricted stock units that vest in three equal annual installments beginning on February 28, 2018."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"On February 28, 2017, the Reporting Person was granted 11,530 restricted stock units that vest in three equal annual installments beginning on February 28, 2018."}],"balance_after":3843,"derivative":{"underlying":"Class A Common Stock","underlying_shares":3843},"source":{"system":"sec-edgar","filing":"0001104659-19-012633","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919012633/a4.xml","form_type":"4"}},{"id":3619046,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2019-03-04T20:01:56.000Z","date":"2019-02-28","kind":"tax_withholding","acquired":false,"shares":2414,"price":17,"value":41038.0,"ownership":{"direct":true},"balance_after":86466,"source":{"system":"sec-edgar","filing":"0001104659-19-012633","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919012633/a4.xml","form_type":"4"}},{"id":3619045,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2019-03-04T20:01:56.000Z","date":"2019-02-28","kind":"exercise","acquired":true,"shares":4675,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":88880,"source":{"system":"sec-edgar","filing":"0001104659-19-012633","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919012633/a4.xml","form_type":"4"}},{"id":3619044,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2019-03-04T20:01:56.000Z","date":"2019-02-28","kind":"exercise","acquired":true,"shares":3843,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":84205,"source":{"system":"sec-edgar","filing":"0001104659-19-012633","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919012633/a4.xml","form_type":"4"}},{"id":3632197,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2019-02-26T20:27:46.000Z","date":"2019-02-24","kind":"exercise","acquired":false,"shares":5677,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units settle in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"On February 24, 2016, the Reporting Person was granted 17,030 restricted stock units that vest in three equal annual installments beginning on February 24, 2017."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"On February 24, 2016, the Reporting Person was granted 17,030 restricted stock units that vest in three equal annual installments beginning on February 24, 2017."}],"balance_after":0,"derivative":{"underlying":"Class A Common Stock","underlying_shares":5677},"source":{"system":"sec-edgar","filing":"0001104659-19-010828","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919010828/a4.xml","form_type":"4"}},{"id":3632196,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2019-02-26T20:27:46.000Z","date":"2019-02-24","kind":"tax_withholding","acquired":false,"shares":1899,"price":17.54,"value":33308.46,"ownership":{"direct":true},"balance_after":80362,"source":{"system":"sec-edgar","filing":"0001104659-19-010828","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919010828/a4.xml","form_type":"4"}},{"id":3632195,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2019-02-26T20:27:46.000Z","date":"2019-02-24","kind":"exercise","acquired":true,"shares":5677,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":82261,"source":{"system":"sec-edgar","filing":"0001104659-19-010828","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465919010828/a4.xml","form_type":"4"}},{"id":3737716,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2018-12-10T20:06:46.000Z","date":"2018-12-10","kind":"purchase","acquired":true,"shares":2000,"price":13,"value":26000.0,"ownership":{"direct":true},"balance_after":76584,"source":{"system":"sec-edgar","filing":"0001104659-18-072174","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465918072174/a4.xml","form_type":"4"}},{"id":3737715,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2018-12-10T20:06:46.000Z","date":"2018-12-04","kind":"purchase","acquired":true,"shares":2000,"price":13.38,"value":26760.0,"ownership":{"direct":true},"balance_after":74584,"source":{"system":"sec-edgar","filing":"0001104659-18-072174","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465918072174/a4.xml","form_type":"4"}},{"id":3766943,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2018-11-13T08:21:06.000Z","date":"2018-11-08","kind":"purchase","acquired":true,"shares":5000,"price":14.12,"value":70600.0,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $14.115 to $14.1299, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth above."}],"balance_after":72584,"source":{"system":"sec-edgar","filing":"0001104659-18-067742","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465918067742/a4.xml","form_type":"4"}},{"id":4023900,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2018-03-01T21:03:55.000Z","date":"2018-02-28","kind":"grant","acquired":true,"shares":14027,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2019."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"These restricted stock units vest in three equal annual installments beginning on February 28, 2019."}],"balance_after":14027,"derivative":{"underlying":"Class A Common Stock","underlying_shares":14027},"source":{"system":"sec-edgar","filing":"0001104659-18-014209","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465918014209/a4.xml","form_type":"4"}},{"id":4023899,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2018-03-01T21:03:55.000Z","date":"2018-02-28","kind":"exercise","acquired":false,"shares":3844,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A Common Stock.  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"On February 28, 2017, the Reporting Person was granted 11,530 restricted stock units that vest in three equal annual installments beginning on February 28, 2018."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"On February 28, 2017, the Reporting Person was granted 11,530 restricted stock units that vest in three equal annual installments beginning on February 28, 2018."}],"balance_after":7686,"derivative":{"underlying":"Class A Common Stock","underlying_shares":3844},"source":{"system":"sec-edgar","filing":"0001104659-18-014209","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465918014209/a4.xml","form_type":"4"}},{"id":4023898,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2018-03-01T21:03:55.000Z","date":"2018-02-28","kind":"tax_withholding","acquired":false,"shares":1114,"price":31.63,"value":35235.82,"ownership":{"direct":true},"balance_after":67584,"source":{"system":"sec-edgar","filing":"0001104659-18-014209","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465918014209/a4.xml","form_type":"4"}},{"id":4023897,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2018-03-01T21:03:55.000Z","date":"2018-02-28","kind":"exercise","acquired":true,"shares":3844,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."}],"balance_after":68698,"source":{"system":"sec-edgar","filing":"0001104659-18-014209","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465918014209/a4.xml","form_type":"4"}},{"id":4030394,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2018-02-27T18:03:21.000Z","date":"2018-02-24","kind":"exercise","acquired":false,"shares":5676,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F4","text":"Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units settle in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"On February 24, 2016, the Reporting Person was granted 17,030 restricted stock units that vest in three equal annual installments beginning on February 24, 2017."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F5","text":"On February 24, 2016, the Reporting Person was granted 17,030 restricted stock units that vest in three equal annual installments beginning on February 24, 2017."}],"balance_after":5677,"derivative":{"underlying":"Class A Common Stock","underlying_shares":5676},"source":{"system":"sec-edgar","filing":"0001104659-18-012912","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465918012912/a4.xml","form_type":"4"}},{"id":4030393,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2018-02-27T18:03:21.000Z","date":"2018-02-24","kind":"tax_withholding","acquired":false,"shares":1764,"price":31.74,"value":55989.36,"ownership":{"direct":true},"balance_after":64855,"source":{"system":"sec-edgar","filing":"0001104659-18-012912","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465918012912/a4.xml","form_type":"4"}},{"id":4030392,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2018-02-27T18:03:21.000Z","date":"2018-02-24","kind":"exercise","acquired":true,"shares":5676,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Total holdings include shares of Class A Common Stock received pursuant to a stock dividend paid on December 22, 2017."}],"balance_after":66619,"source":{"system":"sec-edgar","filing":"0001104659-18-012912","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465918012912/a4.xml","form_type":"4"}},{"id":4134791,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"LP Units of Summit Materials Holdings L.P.","published_at":"2017-12-12T18:04:18.000Z","date":"2017-12-08","kind":"exercise","acquired":false,"shares":60000,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Reflects securities held by trusts for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee."}],"balance_after":332699,"derivative":{"underlying":"Class A Common Stock","underlying_shares":60000},"source":{"system":"sec-edgar","filing":"0001104659-17-072972","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465917072972/a4.xml","form_type":"4"}},{"id":4134790,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2017-12-12T18:04:18.000Z","date":"2017-12-08","kind":"exercise","acquired":true,"shares":60000,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Reflects securities held by trusts for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee."}],"balance_after":60000,"source":{"system":"sec-edgar","filing":"0001104659-17-072972","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465917072972/a4.xml","form_type":"4"}},{"id":4279155,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"LP Units of Summit Materials Holdings L.P.","published_at":"2017-06-16T18:00:38.000Z","date":"2017-06-14","kind":"exercise","acquired":false,"shares":20000,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Reflects securities held by trusts for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee."}],"balance_after":392699,"derivative":{"underlying":"Class A Common Stock","underlying_shares":20000},"source":{"system":"sec-edgar","filing":"0001104659-17-039984","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465917039984/a4.xml","form_type":"4"}},{"id":4279154,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2017-06-16T18:00:38.000Z","date":"2017-06-15","kind":"sale","acquired":false,"shares":20000,"price":28.1965,"value":563930.0,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Reflects securities held by trusts for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee."}],"balance_after":0,"source":{"system":"sec-edgar","filing":"0001104659-17-039984","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465917039984/a4.xml","form_type":"4"}},{"id":4279153,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2017-06-16T18:00:38.000Z","date":"2017-06-14","kind":"exercise","acquired":true,"shares":20000,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Reflects securities held by trusts for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee."}],"balance_after":20000,"source":{"system":"sec-edgar","filing":"0001104659-17-039984","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465917039984/a4.xml","form_type":"4"}},{"id":4370377,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Options (right to buy)","published_at":"2017-03-28T18:10:11.000Z","date":"2017-02-28","kind":"grant","acquired":true,"shares":19216,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"The options vest in three equal annual installments beginning on February 28, 2018."}],"balance_after":19216,"derivative":{"exercise_price":23.89,"expiration_date":"2027-02-28","underlying":"Class A Common Stock","underlying_shares":19216},"source":{"system":"sec-edgar","filing":"0001104659-17-019748","document":"a4a.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465917019748/a4a.xml","form_type":"4/A","original_submission_date":"2017-03-02"}},{"id":4409739,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Options (right to buy)","published_at":"2017-03-02T20:22:58.000Z","date":"2017-02-28","kind":"grant","acquired":true,"shares":19632,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options vest in three equal annual installments beginning on February 28, 2018."}],"balance_after":19632,"derivative":{"exercise_price":23.89,"expiration_date":"2027-02-28","underlying":"Class A Common Stock","underlying_shares":19632},"source":{"system":"sec-edgar","filing":"0001104659-17-013649","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465917013649/a4.xml","form_type":"4"}},{"id":4409738,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2017-03-02T20:22:58.000Z","date":"2017-02-28","kind":"grant","acquired":true,"shares":11530,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each restricted stock unit represents a contingent right to receive one share of Issuer Class A common stock (\"Class A Common Stock\").  The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The restricted stock units vest in three equal annual installments beginning on February 28, 2018."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F2","text":"The restricted stock units vest in three equal annual installments beginning on February 28, 2018."}],"balance_after":11530,"derivative":{"underlying":"Class A Common Stock","underlying_shares":11530},"source":{"system":"sec-edgar","filing":"0001104659-17-013649","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465917013649/a4.xml","form_type":"4"}},{"id":4417885,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Restricted Stock Units","published_at":"2017-02-28T20:18:27.000Z","date":"2017-02-24","kind":"exercise","acquired":false,"shares":5677,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F3","text":"Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units settle in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's compensation committee."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"On February 24, 2016, the Reporting Person was granted 17,030 restricted stock units that vest in three equal annual installments beginning on February 24, 2017."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"On February 24, 2016, the Reporting Person was granted 17,030 restricted stock units that vest in three equal annual installments beginning on February 24, 2017."}],"balance_after":11353,"derivative":{"underlying":"Class A Common Stock","underlying_shares":5677},"source":{"system":"sec-edgar","filing":"0001104659-17-012718","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465917012718/a4.xml","form_type":"4"}},{"id":4417884,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2017-02-28T20:18:27.000Z","date":"2017-02-24","kind":"tax_withholding","acquired":false,"shares":2069,"price":23.75,"value":49138.75,"ownership":{"direct":true},"balance_after":60102,"source":{"system":"sec-edgar","filing":"0001104659-17-012718","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465917012718/a4.xml","form_type":"4"}},{"id":4417883,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2017-02-28T20:18:27.000Z","date":"2017-02-24","kind":"exercise","acquired":true,"shares":5677,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer (\"Class A Common Stock\") on a one-for-one basis."},{"field":"balance_after","element":"sharesOwnedFollowingTransaction","label":"F2","text":"Total holdings include shares of Class A Common Stock received pursuant to a stock dividend paid on December 28, 2016."}],"balance_after":62171,"source":{"system":"sec-edgar","filing":"0001104659-17-012718","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465917012718/a4.xml","form_type":"4"}},{"id":4517077,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"LP Units of Summit Materials Holdings L.P.","published_at":"2016-12-19T18:03:29.000Z","date":"2016-12-15","kind":"exercise","acquired":false,"shares":24000,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Reflects securities held by trusts for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee."}],"balance_after":412699,"derivative":{"underlying":"Class A Common Stock","underlying_shares":24000},"source":{"system":"sec-edgar","filing":"0001104659-16-162859","document":"a4.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465916162859/a4.xml","form_type":"4"}},{"id":4517076,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2016-12-19T18:03:29.000Z","date":"2016-12-16","kind":"sale","acquired":false,"shares":12000,"price":23.63,"value":283560.0,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $23.59 to $23.69, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Reflects securities held by trusts for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee."}],"balance_after":0,"source":{"system":"sec-edgar","filing":"0001104659-16-162859","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465916162859/a4.xml","form_type":"4"}},{"id":4517075,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2016-12-19T18:03:29.000Z","date":"2016-12-16","kind":"sale","acquired":false,"shares":12000,"price":23.59,"value":283080.0,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F3","text":"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $23.57 to $23.65, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Reflects securities held by trusts for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee."}],"balance_after":12000,"source":{"system":"sec-edgar","filing":"0001104659-16-162859","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465916162859/a4.xml","form_type":"4"}},{"id":4517074,"issuer":{"id":16259,"kind":"organization","name":"Summit Materials, Inc.","symbol":"SUM"},"owners":[{"id":452,"kind":"person","name":"Harris Brian James","position":1,"cik":"0001635271","reported_name":"Harris Brian James","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP & Chief Financial Officer"}}],"security":"Class A Common Stock","published_at":"2016-12-19T18:03:29.000Z","date":"2016-12-15","kind":"exercise","acquired":true,"shares":24000,"ownership":{"direct":false,"nature":"See Footnote"},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to the terms of an exchange agreement, dated as of March 11, 2015, the limited partnership units of Summit Materials Holdings L.P. (\"LP Units\") reported herein are exchangeable from and after the first anniversary of the closing of the issuer's initial public offering (subject to the terms of the exchange agreement and vesting requirements, including certain vesting events more fully described in the issuer's Registration Statement on Form S-1 (File No. 333-201058)) for shares of the issuer's Class A common stock on a one-for-one basis."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Reflects securities held by trusts for the benefit of Mr. Harris' family, for which Mr. Harris' spouse serves as trustee."}],"balance_after":24000,"source":{"system":"sec-edgar","filing":"0001104659-16-162859","document":"a4.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1621563/000110465916162859/a4.xml","form_type":"4"}}]}