Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Net income	$ 141,240	$ 61,123	$ 36,330
Other comprehensive income (loss):
Postretirement liability adjustment	(2,229)	(1,925)	1,661
Foreign currency translation adjustment	4,617	4,716	(9,348)
Income (loss) on cash flow hedges	0	(146)
Income (loss) on cash flow hedges			1,206
Less tax effect of other comprehensive (loss) income items	(575)	0	1,578
Other comprehensive income	1,813	2,645	(4,903)
Comprehensive income	143,053	63,768	31,427
Less comprehensive income attributable to Summit Holdings	3,331	3,935	2,226
Comprehensive income attributable to Summit Materials, Inc. / Summit Materials, LLC	139,722	59,833	29,201
Summit Materials, LLC
Net income	120,737	88,597	63,837
Other comprehensive income (loss):
Postretirement liability adjustment	(2,229)	(1,925)	1,661
Foreign currency translation adjustment	4,617	4,716	(9,348)
Income (loss) on cash flow hedges	0	(146)
Income (loss) on cash flow hedges			1,206
Other comprehensive income	2,388	2,645	(6,481)
Comprehensive income attributable to Summit Materials, Inc. / Summit Materials, LLC	$ 123,125	$ 91,242	$ 57,356