Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data	Jun. 30, 2011	Dec. 31, 2010
Condensed Consolidated Balance Sheets
Receivables, allowance for doubtful accounts (in dollars)	$ 3,581	$ 3,332
Debt issuance costs, accumulated amortization (in dollars)	$ 51,315	$ 45,234
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	12,275	12,275
Preferred stock, shares outstanding	12,275	12,275
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	78,868,643	78,414,022