Reconciliation of Average Number of Common Shares and Common Share Equivalents Outstanding (Detail) - shares	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Average number of common shares outstanding	41,938,000	42,112,000	43,664,000
Incremental shares from assumed exercises of stock options	86,000	124,000	149,000
Average number of common shares and common share equivalents outstanding	42,024,000	42,236,000	43,813,000