Loss Reclassified from Accumulated Other Comprehensive Income for Commodity Contracts (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 16, 2016	Jul. 18, 2015	Jul. 16, 2016	Jul. 18, 2015
Accumulated Other Comprehensive Income Loss [Line Items]
Net of tax	$ (803)	$ (1,251)	$ (1,946)	$ (2,838)
Commodity Contract
Accumulated Other Comprehensive Income Loss [Line Items]
Gross loss reclassified from AOCI into income			3,030	4,481
Tax benefit			(1,167)	(1,725)
Net of tax			$ 1,863	$ 2,756