Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 25, 2013	Dec. 25, 2012
Condensed Consolidated Balance Sheets
Receivables, allowance for doubtful accounts (in dollars)	$ 20	$ 22
Property and equipment, accumulated depreciation (in dollars)	$ 286,912	$ 269,052
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	70,249,695	68,977,045
Common stock, shares outstanding	70,249,695	68,977,045