Reconciliation of Average Number of Common Shares and Common Share Equivalents Outstanding (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Average number of common shares outstanding	43,446,000	44,713,000	43,975,000	45,018,000
Incremental shares from assumed exercises of stock options	161,000	224,000	159,000	204,000
Average number of common shares and common share equivalents outstanding	43,607,000	44,937,000	44,134,000	45,222,000