Net Income per Share - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2011	Dec. 25, 2010	Dec. 26, 2009
Earnings Per Share Disclosure [Line Items]
Conversion ratio for Class B to Class A shares	1
Number of shares not included because the performance criteria was not met	3,720
Common Class A
Earnings Per Share Disclosure [Line Items]
Antidilutive securities excluded from computation of earnings per share	213,000	17,600	1,129,000
Common Class A | Performance-Based Options
Earnings Per Share Disclosure [Line Items]
Number of shares not included because the performance criteria was not expected to be met	(65,000)	(100,000)	(229,700)
Number of shares not included because the performance criteria was not met		219,700	125,500