CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	4 Months Ended
Apr. 22, 2017	Apr. 23, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net earnings	$ 15,025	$ 9,851
Other comprehensive income, before tax
Pension and postretirement liability adjustment	41	2
Total other comprehensive income, before tax	41	2
Income tax expense related to items of other comprehensive income	(16)	(1)
Total other comprehensive income, after tax	25	1
Comprehensive income	$ 15,050	$ 9,852

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=51831270

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=51831223

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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Amount before tax of other comprehensive income (loss) attributable to parent entity.

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Amount before tax, after reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss) attributable to parent entity.

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