Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Cash flow from operating activities:
Net income (loss)	$ 125,777	$ 46,126	$ 1,484
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation, depletion, amortization and accretion	193,107	160,633	125,019
Share-based compensation expense	21,140	49,940	19,899
Deferred income tax benefit (expense)	(289,219)	(4,263)	(19,838)
Net gain on asset disposals	(7,638)	(3,102)	(23,087)
Non-cash loss on debt financings	3,856		(9,877)
Other	(2,359)	(1,282)	(1,629)
(Increase) decrease in operating assets, net of acquisitions:
Accounts receivable, net	(3,720)	2,511	3,852
Inventories	(18,609)	(10,297)	4,275
Costs and estimated earnings in excess of billings	(1,825)	(2,684)	6,604
Other current assets	8,703	(5,518)	11,438
Other assets	(3,103)	(2,350)	(1,369)
Increase (decrease) in operating liabilities, net of acquisitions:
Accounts payable	6,192	(5,751)	(4,241)
Accrued expenses	(7,006)	13,196	(14,354)
Billings in excess of costs and estimated earnings	109	700	1,313
Tax receivable agreement liability	273,194	58,145
Other liabilities	(6,416)	(51,141)	(1,286)
Net cash provided by operating activities	292,183	244,863	98,203
Cash flow from investing activities:
Acquisitions, net of cash acquired	(374,930)	(336,958)	(510,017)
Purchases of property, plant and equipment	(194,146)	(153,483)	(88,950)
Proceeds from the sale of property, plant and equipment	17,072	16,868	13,110
Other	(471)	2,921	1,510
Net cash used for investing activities	(552,475)	(470,652)	(584,347)
Cash flow from financing activities:
Proceeds from equity offerings	237,600		1,037,444
Capital issuance costs	(627)	(136)	(61,609)
Proceeds from debt issuances	302,000	354,000	1,748,875
Debt issuance costs	(6,416)	(5,801)	(14,246)
Payments on debt	(16,438)	(120,702)	(1,505,486)
Purchase of noncontrolling interests	(532)		(497,848)
Payments on acquisition-related liabilities	(34,650)	(32,040)	(18,056)
Distributions from partnership	(1,974)	(13,034)	(28,736)
Proceeds from stock option exercises	21,661	440
Other	(869)	(20)	(1)
Net cash provided by financing activities	499,755	182,707	660,337
Impact of cash on foreign currency	701	69	(1,003)
Net increase (decrease) in cash	240,164	(43,013)	173,190
Cash and cash equivalents-beginning of period	143,392	186,405	13,215
Cash and cash equivalents-end of period	383,556	143,392	186,405
Summit Materials, LLC
Cash flow from operating activities:
Net income (loss)	134,041	62,087	2,356
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation, depletion, amortization and accretion	192,213	159,579	124,147
Share-based compensation expense	21,140	49,940	19,899
Deferred income tax benefit (expense)	(7,638)	(3,102)	(23,087)
Net gain on asset disposals	3,856		(9,877)
Goodwill impairment	0
Non-cash loss on debt financings	(23,070)	(8,572)	(19,838)
Other	(2,359)	(1,282)	(1,629)
(Increase) decrease in operating assets, net of acquisitions:
Accounts receivable, net	(3,720)	2,511	3,852
Inventories	(18,609)	(10,297)	4,275
Costs and estimated earnings in excess of billings	(1,825)	(2,684)	6,604
Other current assets	8,703	(5,518)	11,438
Other assets	(3,103)	1,976	(1,369)
Increase (decrease) in operating liabilities, net of acquisitions:
Accounts payable	8,040	(5,706)	(4,241)
Accrued expenses	(6,230)	12,064	(14,354)
Billings in excess of costs and estimated earnings	109	700	1,313
Other liabilities	(6,416)	(6,819)	(1,286)
Net cash provided by operating activities	295,132	244,877	98,203
Cash flow from investing activities:
Acquisitions, net of cash acquired	(374,930)	(336,958)	(510,017)
Purchases of property, plant and equipment	(194,146)	(153,483)	(88,950)
Proceeds from the sale of property, plant and equipment	17,072	16,868	13,110
Other	(471)	2,921	1,510
Net cash used for investing activities	(552,475)	(470,652)	(584,347)
Cash flow from financing activities:
Capital contributions by member	304,541	27,377	507,766
Capital issuance costs	(627)	(136)	(12,930)
Proceeds from debt issuances	302,000	354,000	1,748,875
Debt issuance costs	(6,416)	(5,801)	(14,246)
Payments on debt	(16,438)	(120,702)	(1,505,486)
Purchase of noncontrolling interests	(532)
Payments on acquisition-related liabilities	(32,150)	(29,540)	(18,056)
Distributions from partnership	(51,986)	(42,192)	(46,603)
Other	(866)	(16)
Net cash provided by financing activities	497,526	182,990	659,320
Impact of cash on foreign currency	701	69	(1,003)
Net increase (decrease) in cash	240,884	(42,716)	172,173
Cash and cash equivalents-beginning of period	142,672	185,388	13,215
Cash and cash equivalents-end of period	$ 383,556	$ 142,672	$ 185,388