Accounting for Variable Interest Entities - Narrative (Detail) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 25, 2011	Sep. 26, 2010	Sep. 25, 2011	Sep. 26, 2010	Mar. 27, 2011 BIBP Commodities, Inc. [Member]	Sep. 26, 2010 BIBP Commodities, Inc. [Member]	Sep. 26, 2010 BIBP Commodities, Inc. [Member]
Variable Interest Entity [Line Items]
Cost of cheese purchased					$ 25,100,000	$ 37,100,000	$ 113,600,000
Pre-tax income (loss)	16,846,000	12,540,000	62,693,000	61,132,000	0.0	(658,000.0)	5,500,000
Net income (loss), including noncontrolling interests	$ 11,940,000	$ 8,520,000	$ 42,542,000	$ 40,587,000	$ 0.0	$ (417,000.0)	$ 3,500,000
Earnings per common share - assuming dilution (in dollars per share)	$ 0.44	$ 0.30	$ 1.55	$ 1.42	$ 0.00	$ (0.02)	$ 0.13
Percent of domestic franchisees who entered into cheese purchasing agreement, minimum	99.00%		99.00%