Condensed Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2011	Dec. 31, 2010
10.25% Senior notes due 2014, unamortized discount (in dollars)	$ 9,702	$ 11,035
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares outstanding	0	0
8.25% Senior subordinated notes due 2016.
Interest rate on debt instrument (as a percent)	8.25%	8.25%
10.25% Senior notes due 2014
Interest rate on debt instrument (as a percent)	10.25%	10.25%
6.75% Senior notes due 2020
Interest rate on debt instrument (as a percent)	6.75%	6.75%
Class A
Capital stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized	100,000,000	100,000,000
Common Stock, shares issued	51,604,476	51,426,232
Common Stock, shares outstanding	51,604,476	51,426,232
Class B
Capital stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized	3,000,000	3,000,000
Common Stock, shares issued	1,797,784	1,797,784
Common Stock, shares outstanding	1,797,784	1,797,784
Common Stock, liquidation preference (in dollars)	$ 899	$ 899