Debt (8.25% Senior Suborinated Notes Due 2016) (Details) (USD $)	12 Months Ended				0 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 8.25% Senior subordinated notes due 2016	Apr. 09, 2012 Repayment of Debt 8.25% Senior subordinated notes due 2016	Apr. 09, 2012 Repayment of Debt Premium Paid Over Par 8.25% Senior subordinated notes due 2016
Debt Instrument
Interest rate on debt instrument (as a percent)				8.25%
Aggregate principal amount of notes repurchased					$ 200,000,000
Repayments of Subordinated Debt					215,500,000
Gains (Losses) on Extinguishment of Debt	(41,545,000)	(15,544,000)	(573,000)		(10,600,000)	(8,300,000)
Write off of Deferred Debt Issuance Cost					$ 2,300,000