Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jul. 01, 2014	Dec. 31, 2013
Condensed Consolidated Balance Sheets
Receivables, allowance for doubtful accounts (in dollars)	$ 9	$ 4
Property and equipment, accumulated depreciation (in dollars)	$ 326,489	$ 304,536
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	69,613,056	70,352,257
Common stock, shares outstanding	69,613,056	70,352,257