Senior Notes' Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Condensed Financial Statements, Captions [Line Items]
Net cash (used for) provided by operating activities	$ 79,089	$ 66,412	$ 62,279
Cash flow from investing activities:
Acquisitions, net of cash acquired	(397,854)	(61,601)	(48,757)
Purchase of property, plant and equipment	(76,162)	(65,999)	(45,488)
Proceeds from the sale of property, plant, and equipment	13,366	16,085	8,836
Other	(630)		69
Net cash used for investing activities	(461,280)	(111,515)	(85,340)
Cash flow from financing activities
Proceeds from investment by member	27,617
Net proceeds from debt issuance	762,250	234,681	726,442
Payments on long-term debt	(389,270)	(188,424)	(697,438)
Payments on acquisition-related liabilities	(10,935)	(9,801)	(7,519)
Financing costs	(9,085)	(3,864)	(13,081)
Other	(88)	(3)	(702)
Net cash (used for) provided by financing activities	380,489	32,589	7,702
Net decrease (increase) in cash	(1,702)	(12,514)	(15,359)
Cash - Beginning of period	14,917	27,431	42,790
Cash - end of period	13,215	14,917	27,431
Issuers [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used for) provided by operating activities	(40,964)
Cash flow from investing activities:
Acquisitions, net of cash acquired	(181,754)
Purchase of property, plant and equipment	(4,534)
Net cash used for investing activities	(186,288)
Cash flow from financing activities
Proceeds from investment by member	27,617
Net proceeds from debt issuance	762,250
Loans received from and payments made on loans from other Summit Companies	(170,915)
Payments on long-term debt	(380,065)
Payments on acquisition-related liabilities	(2,000)
Financing costs	(9,085)
Other	(88)
Net cash (used for) provided by financing activities	227,714
Net decrease (increase) in cash	462
Cash - Beginning of period	10,375
Cash - end of period	10,837
Non-Wholly-Owned Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used for) provided by operating activities	11,776	9,003	12,806
Cash flow from investing activities:
Purchase of property, plant and equipment	(14,941)	(24,896)	(12,174)
Proceeds from the sale of property, plant, and equipment		3	69
Other	(1,387)
Net cash used for investing activities	(16,328)	(24,893)	(12,105)
Cash flow from financing activities
Net proceeds from debt issuance			(17)
Loans received from and payments made on loans from other Summit Companies	5,338	15,502	(295)
Payments on long-term debt	(793)
Net cash (used for) provided by financing activities	4,545	15,502	(312)
Net decrease (increase) in cash	(7)	(388)	389
Cash - Beginning of period	9	397	8
Cash - end of period	2	9	397
Wholly-Owned Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used for) provided by operating activities	102,219	44,746	36,649
Cash flow from investing activities:
Acquisitions, net of cash acquired	(216,100)	(61,601)	(48,757)
Purchase of property, plant and equipment	(55,222)	(36,629)	(31,818)
Proceeds from the sale of property, plant, and equipment	13,134	16,020	8,577
Other	(597)		69
Net cash used for investing activities	(258,785)	(82,210)	(71,929)
Cash flow from financing activities
Loans received from and payments made on loans from other Summit Companies	173,166	19,726	39,783
Payments on long-term debt	(8,412)
Payments on acquisition-related liabilities	(8,935)	(9,801)	(7,519)
Other	(2,000)
Net cash (used for) provided by financing activities	153,819	9,925	32,264
Net decrease (increase) in cash	(2,747)	(27,539)	(3,016)
Cash - Beginning of period	3,442	30,981	33,997
Cash - end of period	695	3,442	30,981
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used for) provided by operating activities	8,058	12,895	8,217
Cash flow from investing activities:
Purchase of property, plant and equipment	(1,465)	(1,115)	(734)
Proceeds from the sale of property, plant, and equipment	232	62	190
Net cash used for investing activities	(1,233)	(1,053)	(544)
Cash flow from financing activities
Proceeds from investment by member	1,354
Loans received from and payments made on loans from other Summit Companies	(3,017)	(8,891)	(8,793)
Other			(284)
Net cash (used for) provided by financing activities	(1,663)	(8,891)	(9,077)
Net decrease (increase) in cash	5,162	2,951	(1,404)
Cash - Beginning of period	3,631	680	2,084
Cash - end of period	8,793	3,631	680
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used for) provided by operating activities	(2,000)		(238)
Cash flow from investing activities:
Other	1,354
Net cash used for investing activities	1,354
Cash flow from financing activities
Proceeds from investment by member	(1,354)
Loans received from and payments made on loans from other Summit Companies	(4,572)	2,784	(5,324)
Other	2,000		238
Net cash (used for) provided by financing activities	(3,926)	2,784	(5,086)
Net decrease (increase) in cash	(4,572)	2,784	(5,324)
Cash - Beginning of period	(2,540)	(5,324)
Cash - end of period	(7,112)	(2,540)	(5,324)
Summit Materials LLC (Parent) [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used for) provided by operating activities		(232)	4,845
Cash flow from investing activities:
Purchase of property, plant and equipment		(3,359)	(762)
Net cash used for investing activities		(3,359)	(762)
Cash flow from financing activities
Net proceeds from debt issuance		234,681	726,459
Loans received from and payments made on loans from other Summit Companies		(29,121)	(25,371)
Payments on long-term debt		(188,424)	(697,438)
Financing costs		(3,864)	(13,081)
Other		(3)	(656)
Net cash (used for) provided by financing activities		13,269	(10,087)
Net decrease (increase) in cash		9,678	(6,004)
Cash - Beginning of period		697	6,701
Cash - end of period		$ 10,375	$ 697