Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Consolidated Balance Sheets
Accounts receivable, allowance for doubtful accounts (in dollars)	$ 187	$ 371
Property and equipment, accumulated depreciation and amortization (in dollars)	307,556	249,495
Intangible assets, accumulated amortization (in dollars)	$ 175,070	$ 173,090
Special preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Special preferred stock, shares issued	3	3
Special preferred stock, shares outstanding	3	3
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares issued	52,382,986	51,439,934
Common stock, shares outstanding	52,382,986	51,439,934