Unaudited Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Comprehensive income (loss)
Net income	$ 73,992	$ 84,287	$ 54,957	$ 81,267
Other comprehensive income (loss):
Postretirement liability adjustment	0	0	0	413
Foreign currency translation adjustment	1,970	4,374	(3,179)	8,498
Income on cash flow hedges	87	212	1,443	384
Less tax effect of other comprehensive income (loss) items	(507)	0	428	0
Other comprehensive income (loss):	1,550	4,586	(1,308)	9,295
Comprehensive income	75,542	88,873	53,649	90,562
Less comprehensive income (loss) attributable to the noncontrolling interest in consolidated subsidiaries	0	59	0	(27)
Less comprehensive income attributable to Summit Holdings	5,505	3,135	1,832	2,832
Comprehensive income attributable to Summit Inc.	70,037	85,679	51,817	87,757
Summit Materials, LLC
Comprehensive income (loss)
Net income	90,427	82,633	68,433	81,606
Other comprehensive income (loss):
Postretirement liability adjustment	0	0	0	413
Foreign currency translation adjustment	1,970	4,374	(3,179)	8,498
Income on cash flow hedges	87	212	1,443	384
Other comprehensive income (loss):	2,057	4,586	(1,736)	9,295
Comprehensive income	92,484	87,219	66,697	90,901
Less comprehensive income (loss) attributable to noncontrolling interest	0	59	0	(27)
Comprehensive income attributable to Summit Inc.	$ 92,484	$ 87,160	$ 66,697	$ 90,928