Balance Sheet Parentheticals (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Restricted investments	$ 430	$ 430
Allowance for doubtful accounts receivable	35	35
Accumulated depreciation and amortization, property and equipment	$ 83,416	$ 80,535
Preferred stock, par value per share	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000	5,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.001	$ 0.001
Common stock, shares authorized	900,000	900,000
Treasury stock, shares	380	218
Common Stock
Common stock, shares issued	512,375	480,389