Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 28, 2016	Dec. 29, 2015
Condensed Consolidated Balance Sheets
Receivables, allowance for doubtful accounts (in dollars)	$ 41	$ 6
Property and equipment, accumulated depreciation (in dollars)	425,838	395,886
Intangible assets, accumulated amortization (in dollars)	$ 11,225	$ 10,548
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	70,429,927	70,091,203
Common stock, shares outstanding	70,429,927	70,091,203