3.20.1 html 381 400 1 false 77 0 false 8 false false R1.htm 0001000 - Document - Cover Sheet http://www.summitmaterials.com/role/Cover Cover Cover 1 false false R2.htm 1001000 - Statement - Consolidated Balance Sheets Sheet http://www.summitmaterials.com/role/ConsolidatedBalanceSheets Consolidated Balance Sheets Statements 2 false false R3.htm 1001501 - Statement - Consolidated Balance Sheets (Parenthetical) Sheet http://www.summitmaterials.com/role/ConsolidatedBalanceSheetsParenthetical Consolidated Balance Sheets (Parenthetical) Statements 3 false false R4.htm 1002000 - Statement - Unaudited Consolidated Statements of Operations Sheet http://www.summitmaterials.com/role/UnauditedConsolidatedStatementsOfOperations Unaudited Consolidated Statements of Operations Statements 4 false false R5.htm 1004000 - Statement - Unaudited Consolidated Statements of Comprehensive Income Sheet http://www.summitmaterials.com/role/UnauditedConsolidatedStatementsOfComprehensiveIncome Unaudited Consolidated Statements of Comprehensive Income Statements 5 false false R6.htm 1005000 - Statement - Unaudited Consolidated Statements of Cash Flows Sheet http://www.summitmaterials.com/role/UnauditedConsolidatedStatementsOfCashFlows Unaudited Consolidated Statements of Cash Flows Statements 6 false false R7.htm 1006000 - Statement - Unaudited Consolidated Statements of Changes in Stockholders' Equity / Members' Interest and Redeemable Noncontrolling Interest Sheet http://www.summitmaterials.com/role/UnauditedConsolidatedStatementsOfChangesInStockholdersEquityMembersInterestAndRedeemableNoncontrollingInterest Unaudited Consolidated Statements of Changes in Stockholders' Equity / Members' Interest and Redeemable Noncontrolling Interest Statements 7 false false R8.htm 2101100 - Disclosure - SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Sheet http://www.summitmaterials.com/role/SummaryOfOrganizationAndSignificantAccountingPolicies SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Notes 8 false false R9.htm 2102100 - Disclosure - GOODWILL AND INTANGIBLES Sheet http://www.summitmaterials.com/role/GoodwillAndIntangibles GOODWILL AND INTANGIBLES Notes 9 false false R10.htm 2103100 - Disclosure - REVENUE RECOGNITION Sheet http://www.summitmaterials.com/role/RevenueRecognition REVENUE RECOGNITION Notes 10 false false R11.htm 2104100 - Disclosure - INVENTORIES Sheet http://www.summitmaterials.com/role/Inventories INVENTORIES Notes 11 false false R12.htm 2105100 - Disclosure - ACCRUED EXPENSES Sheet http://www.summitmaterials.com/role/AccruedExpenses ACCRUED EXPENSES Notes 12 false false R13.htm 2106100 - Disclosure - DEBT Sheet http://www.summitmaterials.com/role/Debt DEBT Notes 13 false false R14.htm 2107100 - Disclosure - INCOME TAXES Sheet http://www.summitmaterials.com/role/IncomeTaxes INCOME TAXES Notes 14 false false R15.htm 2108100 - Disclosure - EARNINGS PER SHARE Sheet http://www.summitmaterials.com/role/EarningsPerShare EARNINGS PER SHARE Notes 15 false false R16.htm 2109100 - Disclosure - STOCKHOLDERS' EQUITY/MEMBERS' INTEREST Sheet http://www.summitmaterials.com/role/StockholdersEquityMembersInterest STOCKHOLDERS' EQUITY/MEMBERS' INTEREST Notes 16 false false R17.htm 2111100 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION Sheet http://www.summitmaterials.com/role/SupplementalCashFlowInformation SUPPLEMENTAL CASH FLOW INFORMATION Notes 17 false false R18.htm 2113100 - Disclosure - LEASES Sheet http://www.summitmaterials.com/role/Leases LEASES Notes 18 false false R19.htm 2114100 - Disclosure - COMMITMENTS AND CONTINGENCIES Sheet http://www.summitmaterials.com/role/CommitmentsAndContingencies COMMITMENTS AND CONTINGENCIES Notes 19 false false R20.htm 2115100 - Disclosure - FAIR VALUE Sheet http://www.summitmaterials.com/role/FairValue FAIR VALUE Notes 20 false false R21.htm 2116100 - Disclosure - SEGMENT INFORMATION Sheet http://www.summitmaterials.com/role/SegmentInformation SEGMENT INFORMATION Notes 21 false false R22.htm 2125100 - Disclosure - GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION Sheet http://www.summitmaterials.com/role/GuarantorAndNonGuarantorFinancialInformation GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION Notes 22 false false R23.htm 2201201 - Disclosure - SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES - (Policies) Sheet http://www.summitmaterials.com/role/SummaryOfOrganizationAndSignificantAccountingPoliciesPolicies SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES - (Policies) Policies 23 false false R24.htm 2302301 - Disclosure - GOODWILL AND INTANGIBLES - (Tables) Sheet http://www.summitmaterials.com/role/GoodwillAndIntangiblesTables GOODWILL AND INTANGIBLES - (Tables) Tables http://www.summitmaterials.com/role/GoodwillAndIntangibles 24 false false R25.htm 2303301 - Disclosure - REVENUE RECOGNITION - (Tables) Sheet http://www.summitmaterials.com/role/RevenueRecognitionTables REVENUE RECOGNITION - (Tables) Tables http://www.summitmaterials.com/role/RevenueRecognition 25 false false R26.htm 2304301 - Disclosure - INVENTORIES - (Tables) Sheet http://www.summitmaterials.com/role/InventoriesTables INVENTORIES - (Tables) Tables http://www.summitmaterials.com/role/Inventories 26 false false R27.htm 2305301 - Disclosure - ACCRUED EXPENSES - (Tables) Sheet http://www.summitmaterials.com/role/AccruedExpensesTables ACCRUED EXPENSES - (Tables) Tables http://www.summitmaterials.com/role/AccruedExpenses 27 false false R28.htm 2306301 - Disclosure - DEBT - (Tables) Sheet http://www.summitmaterials.com/role/DebtTables DEBT - (Tables) Tables 28 false false R29.htm 2308301 - Disclosure - EARNINGS PER SHARE - (Tables) Sheet http://www.summitmaterials.com/role/EarningsPerShareTables EARNINGS PER SHARE - (Tables) Tables http://www.summitmaterials.com/role/EarningsPerShare 29 false false R30.htm 2309301 - Disclosure - STOCKHOLDERS' EQUITY/MEMBERS' INTEREST - (Tables) Sheet http://www.summitmaterials.com/role/StockholdersEquityMembersInterestTables STOCKHOLDERS' EQUITY/MEMBERS' INTEREST - (Tables) Tables http://www.summitmaterials.com/role/StockholdersEquityMembersInterest 30 false false R31.htm 2311301 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION - (Tables) Sheet http://www.summitmaterials.com/role/SupplementalCashFlowInformationTables SUPPLEMENTAL CASH FLOW INFORMATION - (Tables) Tables http://www.summitmaterials.com/role/SupplementalCashFlowInformation 31 false false R32.htm 2313301 - Disclosure - LEASES - (Tables) Sheet http://www.summitmaterials.com/role/LeasesTables LEASES - (Tables) Tables 32 false false R33.htm 2315301 - Disclosure - FAIR VALUE - (Tables) Sheet http://www.summitmaterials.com/role/FairValueTables FAIR VALUE - (Tables) Tables http://www.summitmaterials.com/role/FairValue 33 false false R34.htm 2316301 - Disclosure - SEGMENT INFORMATION - (Tables) Sheet http://www.summitmaterials.com/role/SegmentInformationTables SEGMENT INFORMATION - (Tables) Tables http://www.summitmaterials.com/role/SegmentInformation 34 false false R35.htm 2325301 - Disclosure - GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - (Tables) Sheet http://www.summitmaterials.com/role/GuarantorAndNonGuarantorFinancialInformationTables GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - (Tables) Tables http://www.summitmaterials.com/role/GuarantorAndNonGuarantorFinancialInformation 35 false false R36.htm 2401402 - Disclosure - SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES - General Information (Details) Sheet http://www.summitmaterials.com/role/SummaryOfOrganizationAndSignificantAccountingPoliciesGeneralInformationDetails SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES - General Information (Details) Details 36 false false R37.htm 2401403 - Disclosure - SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES - Business and Credit Concentration (Details) Sheet http://www.summitmaterials.com/role/SummaryOfOrganizationAndSignificantAccountingPoliciesBusinessAndCreditConcentrationDetails SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES - Business and Credit Concentration (Details) Details 37 false false R38.htm 2402402 - Disclosure - GOODWILL AND INTANGIBLES - Summary of Goodwill by Reportable Segments (Details) Sheet http://www.summitmaterials.com/role/GoodwillAndIntangiblesSummaryOfGoodwillByReportableSegmentsDetails GOODWILL AND INTANGIBLES - Summary of Goodwill by Reportable Segments (Details) Details 38 false false R39.htm 2402403 - Disclosure - GOODWILL AND INTANGIBLES - Intangible Assets By Type (Details) Sheet http://www.summitmaterials.com/role/GoodwillAndIntangiblesIntangibleAssetsByTypeDetails GOODWILL AND INTANGIBLES - Intangible Assets By Type (Details) Details 39 false false R40.htm 2402404 - Disclosure - GOODWILL AND INTANGIBLES - Amortization Expense (Details) Sheet http://www.summitmaterials.com/role/GoodwillAndIntangiblesAmortizationExpenseDetails GOODWILL AND INTANGIBLES - Amortization Expense (Details) Details 40 false false R41.htm 2403402 - Disclosure - REVENUE RECOGNITION - By Product (Details) Sheet http://www.summitmaterials.com/role/RevenueRecognitionByProductDetails REVENUE RECOGNITION - By Product (Details) Details 41 false false R42.htm 2403403 - Disclosure - REVENUE RECOGNITION - Summary of Accounts Receivable, Net (Details) Sheet http://www.summitmaterials.com/role/RevenueRecognitionSummaryOfAccountsReceivableNetDetails REVENUE RECOGNITION - Summary of Accounts Receivable, Net (Details) Details 42 false false R43.htm 2404402 - Disclosure - INVENTORIES - Components of Inventories (Details) Sheet http://www.summitmaterials.com/role/InventoriesComponentsOfInventoriesDetails INVENTORIES - Components of Inventories (Details) Details 43 false false R44.htm 2405402 - Disclosure - ACCRUED EXPENSES - Components of Accrued Expenses (Details) Sheet http://www.summitmaterials.com/role/AccruedExpensesComponentsOfAccruedExpensesDetails ACCRUED EXPENSES - Components of Accrued Expenses (Details) Details 44 false false R45.htm 2406402 - Disclosure - DEBT - Schedule of Debt (Details) Sheet http://www.summitmaterials.com/role/DebtScheduleOfDebtDetails DEBT - Schedule of Debt (Details) Details 45 false false R46.htm 2406403 - Disclosure - DEBT - Schedule of Contractual Payments of Long-Term Debt (Details) Sheet http://www.summitmaterials.com/role/DebtScheduleOfContractualPaymentsOfLongTermDebtDetails DEBT - Schedule of Contractual Payments of Long-Term Debt (Details) Details 46 false false R47.htm 2406404 - Disclosure - DEBT - Senior Notes (Details) Notes http://www.summitmaterials.com/role/DebtSeniorNotesDetails DEBT - Senior Notes (Details) Details 47 false false R48.htm 2406405 - Disclosure - DEBT - Senior Secured Credit Facilities (Details) Sheet http://www.summitmaterials.com/role/DebtSeniorSecuredCreditFacilitiesDetails DEBT - Senior Secured Credit Facilities (Details) Details 48 false false R49.htm 2406406 - Disclosure - DEBT - Summary of Activity for Deferred Financing Fees (Details) Sheet http://www.summitmaterials.com/role/DebtSummaryOfActivityForDeferredFinancingFeesDetails DEBT - Summary of Activity for Deferred Financing Fees (Details) Details 49 false false R50.htm 2406407 - Disclosure - DEBT - Other (Details) Sheet http://www.summitmaterials.com/role/DebtOtherDetails DEBT - Other (Details) Details 50 false false R51.htm 2407401 - Disclosure - INCOME TAXES - Narrative (Details) Sheet http://www.summitmaterials.com/role/IncomeTaxesNarrativeDetails INCOME TAXES - Narrative (Details) Details 51 false false R52.htm 2408402 - Disclosure - EARNINGS PER SHARE - Schedule of Basic to Diluted Income Per Share (Details) Sheet http://www.summitmaterials.com/role/EarningsPerShareScheduleOfBasicToDilutedIncomePerShareDetails EARNINGS PER SHARE - Schedule of Basic to Diluted Income Per Share (Details) Details 52 false false R53.htm 2409402 - Disclosure - STOCKHOLDERS' EQUITY/MEMBERS' INTEREST - Equity Offerings (Details) Sheet http://www.summitmaterials.com/role/StockholdersEquityMembersInterestEquityOfferingsDetails STOCKHOLDERS' EQUITY/MEMBERS' INTEREST - Equity Offerings (Details) Details 53 false false R54.htm 2409403 - Disclosure - STOCKHOLDERS' EQUITY/MEMBERS' INTEREST - Accumulated Other Comprehensive Income (Loss) (Details) Sheet http://www.summitmaterials.com/role/StockholdersEquityMembersInterestAccumulatedOtherComprehensiveIncomeLossDetails STOCKHOLDERS' EQUITY/MEMBERS' INTEREST - Accumulated Other Comprehensive Income (Loss) (Details) Details 54 false false R55.htm 2411402 - Disclosure - SUPPLEMENTAL CASH FLOW INFORMATION - Schedule of Supplemental Cash Flow Information (Details) Sheet http://www.summitmaterials.com/role/SupplementalCashFlowInformationScheduleOfSupplementalCashFlowInformationDetails SUPPLEMENTAL CASH FLOW INFORMATION - Schedule of Supplemental Cash Flow Information (Details) Details 55 false false R56.htm 2413402 - Disclosure - LEASES - Operating and Finance Leases (Details) Sheet http://www.summitmaterials.com/role/LeasesOperatingAndFinanceLeasesDetails LEASES - Operating and Finance Leases (Details) Details 56 false false R57.htm 2414401 - Disclosure - COMMITMENTS AND CONTINGENCIES - Additional Information (Details) Sheet http://www.summitmaterials.com/role/CommitmentsAndContingenciesAdditionalInformationDetails COMMITMENTS AND CONTINGENCIES - Additional Information (Details) Details 57 false false R58.htm 2415402 - Disclosure - FAIR VALUE - Fair Value Measurements (Details) Sheet http://www.summitmaterials.com/role/FairValueFairValueMeasurementsDetails FAIR VALUE - Fair Value Measurements (Details) Details 58 false false R59.htm 2415403 - Disclosure - FAIR VALUE - Carrying Value and Fair Value of Financial Instruments (Details) Sheet http://www.summitmaterials.com/role/FairValueCarryingValueAndFairValueOfFinancialInstrumentsDetails FAIR VALUE - Carrying Value and Fair Value of Financial Instruments (Details) Details 59 false false R60.htm 2416402 - Disclosure - SEGMENT INFORMATION - Financial Data (Details) Sheet http://www.summitmaterials.com/role/SegmentInformationFinancialDataDetails SEGMENT INFORMATION - Financial Data (Details) Details 60 false false R61.htm 2425402 - Disclosure - GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - Schedule of Condensed Consolidating Balance Sheets (Details) Sheet http://www.summitmaterials.com/role/GuarantorAndNonGuarantorFinancialInformationScheduleOfCondensedConsolidatingBalanceSheetsDetails GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - Schedule of Condensed Consolidating Balance Sheets (Details) Details 61 false false R62.htm 2425403 - Disclosure - GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - Schedule of Condensed Consolidating Statements of Operations and Comprehensive Loss (Details) Sheet http://www.summitmaterials.com/role/GuarantorAndNonGuarantorFinancialInformationScheduleOfCondensedConsolidatingStatementsOfOperationsAndComprehensiveLossDetails GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - Schedule of Condensed Consolidating Statements of Operations and Comprehensive Loss (Details) Details 62 false false R63.htm 2425404 - Disclosure - GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - Schedule of Condensed Consolidating Statements of Cash Flows (Details) Sheet http://www.summitmaterials.com/role/GuarantorAndNonGuarantorFinancialInformationScheduleOfCondensedConsolidatingStatementsOfCashFlowsDetails GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - Schedule of Condensed Consolidating Statements of Cash Flows (Details) Details 63 false false All Reports Book All Reports a10q12020.htm exhibit99110q12020.htm ex31110q12020.htm ex31210q12020.htm ex31310q12020.htm ex31410q12020.htm ex32110q12020.htm ex32210q12020.htm ex32310q12020.htm ex32410q12020.htm exhibit95110q12020.htm sum-20200328.xsd sum-20200328_cal.xml sum-20200328_def.xml sum-20200328_lab.xml sum-20200328_pre.xml corpstructurea18.jpg sum20180630x10q002a02.jpg http://fasb.org/us-gaap/2019-01-31 http://xbrl.sec.gov/dei/2019-01-31 http://fasb.org/srt/2019-01-31 true true