Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016
Condensed Consolidating Statements of Operations
Net cash provided by operating activities	$ 132,433	$ 84,523
Cash flow from investing activities:
Acquisitions, net of cash acquired	(371,479)	(331,463)
Purchase of property, plant and equipment	(147,478)	(121,945)
Proceeds from the sale of property, plant, and equipment	13,290	16,222
Other	182	1,500
Net cash used for investing activities	(505,485)	(435,686)
Cash flow from financing activities:
Capital issuance costs	(627)	(136)
Net proceeds from debt issuance	302,000	354,000
Payments on long-term debt	(12,887)	(114,254)
Payments on acquisition-related liabilities	(22,616)	(28,920)
Financing costs	(5,317)	(5,675)
Distributions from partnership	(109)	(9,049)
Other	17,964	105
Net cash provided by financing activities	516,008	196,071
Impact of cash on foreign currency	734	330
Net increase (decrease) in cash	143,690	(154,762)
Cash and cash equivalents-beginning of period	143,392	186,405
Cash and cash equivalents-end of period	287,082	31,643
Summit Materials, LLC
Condensed Consolidating Statements of Operations
Net cash provided by operating activities	132,895	84,523
Cash flow from investing activities:
Acquisitions, net of cash acquired	(371,479)	(331,463)
Purchase of property, plant and equipment	(147,478)	(121,945)
Proceeds from the sale of property, plant, and equipment	13,290	16,222
Other	182	1,500
Net cash used for investing activities	(505,485)	(435,686)
Cash flow from financing activities:
Proceeds from investment by member	256,667	113
Capital issuance costs	(627)	(136)
Net proceeds from debt issuance	302,000	354,000
Payments on long-term debt	(12,887)	(114,254)
Payments on acquisition-related liabilities	(20,116)	(26,420)
Financing costs	(5,317)	(5,675)
Distributions from partnership	(2,609)	(27,993)
Other	(845)	(8)
Net cash provided by financing activities	516,266	179,627
Impact of cash on foreign currency	734	330
Net increase (decrease) in cash	144,410	(171,206)
Cash and cash equivalents-beginning of period	142,672	185,388
Cash and cash equivalents-end of period	287,082	14,182
Summit Materials, LLC | Eliminations
Cash flow from financing activities:
Loans received from and payments made on loans from other Summit Companies	(3,906)	(6,048)
Net cash provided by financing activities	(3,906)	(6,048)
Net increase (decrease) in cash	(3,906)	(6,048)
Cash and cash equivalents-beginning of period	(10,666)	(11,600)
Cash and cash equivalents-end of period	(14,572)	(17,648)
Summit Materials, LLC | Issuers
Condensed Consolidating Statements of Operations
Net cash provided by operating activities	(92,840)	(135,318)
Cash flow from investing activities:
Acquisitions, net of cash acquired	(24,538)	(42,844)
Purchase of property, plant and equipment	(4,994)	(3,769)
Net cash used for investing activities	(29,532)	(46,613)
Cash flow from financing activities:
Proceeds from investment by member	(3,409)	(476,386)
Capital issuance costs	(627)	(136)
Net proceeds from debt issuance	302,000	354,000
Loans received from and payments made on loans from other Summit Companies	(10,787)	281,013
Payments on long-term debt	(6,874)	(108,875)
Payments on acquisition-related liabilities		(400)
Financing costs	(5,317)	(5,675)
Distributions from partnership	(2,609)	(27,993)
Other	(536)
Net cash provided by financing activities	271,841	15,548
Net increase (decrease) in cash	149,469	(166,383)
Cash and cash equivalents-beginning of period	133,862	180,712
Cash and cash equivalents-end of period	283,331	14,329
Summit Materials, LLC | Guarantors
Condensed Consolidating Statements of Operations
Net cash provided by operating activities	198,890	219,647
Cash flow from investing activities:
Acquisitions, net of cash acquired	(321,340)	(288,619)
Purchase of property, plant and equipment	(137,505)	(117,760)
Proceeds from the sale of property, plant, and equipment	13,231	16,129
Other	182	1,500
Net cash used for investing activities	(445,432)	(388,750)
Cash flow from financing activities:
Proceeds from investment by member	249,359	476,499
Loans received from and payments made on loans from other Summit Companies	20,975	(275,274)
Payments on long-term debt	(6,009)	(5,379)
Payments on acquisition-related liabilities	(20,116)	(26,020)
Other	(288)	(8)
Net cash provided by financing activities	243,921	169,818
Net increase (decrease) in cash	(2,621)	715
Cash and cash equivalents-beginning of period	4,820	4,068
Cash and cash equivalents-end of period	2,199	4,783
Summit Materials, LLC | Non Guarantors
Condensed Consolidating Statements of Operations
Net cash provided by operating activities	26,845	194
Cash flow from investing activities:
Acquisitions, net of cash acquired	(25,601)
Purchase of property, plant and equipment	(4,979)	(416)
Proceeds from the sale of property, plant, and equipment	59	93
Net cash used for investing activities	(30,521)	(323)
Cash flow from financing activities:
Proceeds from investment by member	10,717
Loans received from and payments made on loans from other Summit Companies	(6,282)	309
Payments on long-term debt	(4)
Other	(21)
Net cash provided by financing activities	4,410	309
Impact of cash on foreign currency	734	330
Net increase (decrease) in cash	1,468	510
Cash and cash equivalents-beginning of period	14,656	12,208
Cash and cash equivalents-end of period	$ 16,124	$ 12,718