Consolidated Statements of Comprehensive Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Jan. 02, 2016	Dec. 27, 2014
Net income (loss)	$ 46,126	$ 1,484	$ (6,282)
Other comprehensive income (loss):
Postretirement curtailment adjustment			(1,346)
Postretirement liability adjustment	426	2,123	(3,919)
Foreign currency translation adjustment	2,125	(14,099)	(5,816)
Loss on cash flow hedges	(1,529)	(944)
Other comprehensive income (loss)	1,022	(12,920)	(11,081)
Comprehensive income (loss)	47,148	(11,436)	(17,363)
Less comprehensive income (loss) attributable to the noncontrolling interest in consolidated subsidiaries	16	(1,826)	915
Less comprehensive income (loss) attributable Summit Holdings	9,803	(34,533)	(18,278)
Comprehensive income attributable to Summit Materials, Inc. / Summit Materials, LLC	37,329	24,923
Summit Materials, LLC
Net income (loss)	62,087	2,356	(6,282)
Other comprehensive income (loss):
Postretirement curtailment adjustment			(1,346)
Postretirement liability adjustment	426	2,123	(3,919)
Foreign currency translation adjustment	2,125	(14,099)	(5,816)
Loss on cash flow hedges	(1,529)	(944)
Other comprehensive income (loss)	1,022	(12,920)	(11,081)
Comprehensive income (loss)	63,109	(10,564)	(17,363)
Less comprehensive loss attributable to noncontrolling interest	16	(1,826)	915
Comprehensive income attributable to Summit Materials, Inc. / Summit Materials, LLC	$ 63,093	$ (8,738)	$ (18,278)