Accounting for Variable Interest Entities (Narrative) (Detail) (USD $)		3 Months Ended	12 Months Ended
	Dec. 25, 2011	Mar. 27, 2011 BIBP Commodities, Inc. [Member]	Dec. 26, 2010 BIBP Commodities, Inc. [Member]	Dec. 27, 2009 BIBP Commodities, Inc. [Member]
Variable Interest Entities
Cost of cheese purchased		$ 25,100,000	$ 153,000,000	$ 142,400,000
Pre-tax income (loss)		0	21,000,000	22,500,000
Net income, including noncontrolling interests		0	13,500,000	14,600,000
Earnings per common share - assuming dilution (in dollars per share)		$ 0.00	$ 0.51	$ 0.52
Accumulated deficit			14,200,000
Intercompany cost of sales			$ 14,200,000
Percent of domestic franchisees who entered into cheese purchasing agreement, minimum	99.00%