Loss Reclassified From AOCI for Commodity Contracts (Detail) - USD ($) $ in Thousands		4 Months Ended
		Apr. 20, 2019	Apr. 21, 2018
Accumulated Other Comprehensive Income Loss [Line Items]
Net of tax		$ (2,178)	$ 297
Cash Flow Hedge Items
Accumulated Other Comprehensive Income Loss [Line Items]
Gross (gain) loss reclassified from AOCI into income	[1]	(2,913)	397
Tax (benefit) expense	[1]	735	(100)
Net of tax	[1]	(2,178)	297
Commodity Contract | Cash Flow Hedge Items
Accumulated Other Comprehensive Income Loss [Line Items]
Gross (gain) loss reclassified from AOCI into income	[1],[2]	(2,957)	353
Tax (benefit) expense		747	(89)
Net of tax		$ (2,210)	$ 264

[1] Amounts in parentheses indicate debits to determine net income (loss).

[2] Amounts are presented as an adjustment to reconcile net income (loss) to net cash provided by operating activities on the     Condensed Consolidated Statements of Cash Flows.