Reconciliation of Average Number of Common Shares Outstanding to Average Number of Diluted Shares Outstanding (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 25, 2011	Jun. 30, 2012	Jun. 25, 2011
Earnings Per Share Disclosure [Line Items]
Average number of common shares outstanding	46,915,000	47,782,000	46,856,000	47,826,000
Incremental shares from assumed exercises of stock options	189,000	130,000	227,000	81,000
Average number of common shares and common share equivalents outstanding	47,104,000	47,912,000	47,083,000	47,907,000