Summary of Company's Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	4 Months Ended
	Apr. 20, 2019	Apr. 21, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 3,179	$ 3,375
Performance Contingent Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	2,356	2,853
Time-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	448
Deferred stock
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 375	$ 522