Consolidated Statements of Comprehensive Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Net income (loss)	$ 52,088	$ 21,505	$ (3,020)	$ (21,029)
Other comprehensive income (loss):
Postretirement liability adjustment	413		413
Foreign currency translation adjustment	3,418	635	4,124	5,277
(Loss) income on cash flow hedges	(240)	(1,058)	172	(3,292)
Other comprehensive income (loss)	3,591	(423)	4,709	1,985
Comprehensive loss	55,679	21,082	1,689	(19,044)
Less comprehensive income (loss) attributable to the noncontrolling interest in consolidated subsidiaries	12	44	(86)	(35)
Less comprehensive income (loss) attributable Summit Holdings	1,145	8,051	(303)	(12,076)
Comprehensive income (loss) attributable to Summit Materials, Inc. / Summit Materials, LLC	54,522	12,987	2,078	(6,933)
Summit Materials, LLC
Net income (loss)	53,827	21,759	(1,027)	(20,484)
Other comprehensive income (loss):
Postretirement liability adjustment	413		413
Foreign currency translation adjustment	3,418	635	4,124	5,277
(Loss) income on cash flow hedges	(240)	(1,058)	172	(3,292)
Other comprehensive income (loss)	3,591	(423)	4,709	1,985
Comprehensive loss	57,418	21,336	3,682	(18,499)
Less comprehensive income (loss) attributable to noncontrolling interest	12	44	(86)	(35)
Comprehensive income (loss) attributable to Summit Materials, Inc. / Summit Materials, LLC	$ 57,406	$ 21,292	$ 3,768	$ (18,464)