Consolidated Statements of Comprehensive Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Net income (loss)	$ 125,777	$ 46,126	$ 1,484
Other comprehensive income (loss):
Postretirement curtailment adjustment	429
Postretirement liability adjustment	699	426	2,123
Foreign currency translation adjustment	7,768	2,125	(14,099)
Income (loss) on cash flow hedges	1,413	(1,529)	(944)
Less tax effect of other comprehensive income (loss) items	(288)
Other comprehensive income (loss)	10,021	1,022	(12,920)
Comprehensive income (loss)	135,798	47,148	(11,436)
Less comprehensive income (loss) attributable to the noncontrolling interest in consolidated subsidiaries	(27)	16	(1,826)
Less comprehensive income (loss) attributable Summit Holdings	4,360	9,803	(34,533)
Comprehensive income attributable to Summit Materials, Inc. / Summit Materials, LLC	131,465	37,329	24,923
Summit Materials, LLC
Net income (loss)	134,041	62,087	2,356
Other comprehensive income (loss):
Postretirement curtailment adjustment	429
Postretirement liability adjustment	699	426	2,123
Foreign currency translation adjustment	7,768	2,125	(14,099)
Income (loss) on cash flow hedges	1,413	(1,529)	(944)
Other comprehensive income (loss)	10,309	1,022	(12,920)
Comprehensive income (loss)	144,350	63,109	(10,564)
Less comprehensive income (loss) attributable to noncontrolling interest	(27)	16	(1,826)
Comprehensive income attributable to Summit Materials, Inc. / Summit Materials, LLC	$ 144,377	$ 63,093	$ (8,738)