Debt 9.5% Senior Notes due 2018 (Details) (USD $)	12 Months Ended					12 Months Ended						12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Other Assets	Dec. 31, 2011 Other Assets	Dec. 31, 2012 Senior Notes, due Oct 2018, fixed rate 9.5%	Dec. 31, 2011 Senior Notes, due Oct 2018, fixed rate 9.5%	Dec. 31, 2010 Senior Notes, due Oct 2018, fixed rate 9.5%	Oct. 19, 2010 Senior Notes, due Oct 2018, fixed rate 9.5%	Dec. 31, 2012 Senior Secured Revolving Credit Facility	Oct. 08, 2010 Senior Secured Revolving Credit Facility	Dec. 31, 2012 October 2010 Refinancing	Dec. 31, 2011 October 2010 Refinancing	Dec. 31, 2010 October 2010 Refinancing	Oct. 08, 2010 October 2010 Refinancing
Debt Instrument [Line Items]
Face amount of debt									$ 825,000,000		$ 50,000,000
State interest rate on debt									9.50%
Effective interest rate on debt	7.80%					10.90%
Maximum amount of aggregate pincipal redeemed with net proceeds raised in one or more equity offerings	35.00%
Compulsory purchase price under change of control	101.00%
Compulsory purchase price under sale of assets under certain circumstances	100.00%
Minimum aggregate principal amount required for trustees or other holders to declare principal and accrued interest immediately due	25.00%	25.00%
Deferred financing costs net				16,800,000	21,700,000	28,200,000				800,000
Interest expense debt and debt discount	114,338,000	132,707,000	171,537,000			2,600,000	2,700,000	600,000				3,400,000	3,400,000	600,000
Loss on extinguishment of debt	5,554,000	11,159,000	107,003,000			2,300,000	3,100,000	800,000				2,700,000	3,100,000	500,000
Discount on debt	23,300,000	29,400,000													29,600,000
2013	7,400,000
2014	7,400,000
2015	7,400,000
2016	7,400,000
2017	442,400,000
Thereafter	760,800,000
Total debt	$ 1,232,800,000