Reconciliation of Average Number of Common Shares and Common Share Equivalents Outstanding (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 25, 2016	Jun. 27, 2015	Jun. 25, 2016	Jun. 27, 2015
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Average number of common shares outstanding	42,235,000	43,892,000	42,315,000	44,240,000
Incremental shares from assumed exercises of stock options	122,000	141,000	109,000	157,000
Average number of common shares and common share equivalents outstanding	42,357,000	44,033,000	42,424,000	44,397,000