Income taxes - Provision (Benefit) for Income Taxes on Income from Continuing Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 28, 2014	Dec. 29, 2013
Current
Federal	$ 114,161	$ 139,710	$ 50,564
State and other	12,795	23,114	(22,105)
Foreign	1,849	1,100	1,000
Total	128,805	163,924	29,459
Deferred
Federal	76,816	51,245	(28,151)
State and other	(2,247)	20,232	10,562
Foreign	(1,060)	(930)	1,252
Total	73,509	70,547	(16,337)
Total
Federal	190,977	190,955	22,413
State and other	10,548	43,346	(11,543)
Foreign	789	170	2,252
Total	$ 202,314	$ 234,471	$ 13,122