Debt Senior Notes (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Debt Instrument [Line Items]
Senior notes	$ 227,870,000	$ 227,870,000		$ 227,670,000
Preferred Stock, Dividend Rate, Percentage		9.75%
Restricted Payments Basket	49,000,000	49,000,000
Preferred shares redeemed during period		2,000
Redemption of preferred shares		50,352,000	0
Dividends, Preferred Stock	1,200,000	(1,219,000)
2018 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	8.625%	8.625%
Senior notes	230,000,000	230,000,000
2017 Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Convertible Subordinated Debt	57,500,000	57,500,000
Debt Instrument, Interest Rate, Stated Percentage	3.25%	3.25%
Debt Instrument, Convertible, Conversion Ratio	42.0159
Debt Instrument Convertible Principal Amount Used In Conversion Rate Calculation	1,000	1,000
Debt Instrument, Convertible, Conversion Price	$ 23.80	$ 23.80
Stock Issued During Period, Shares, Other	2,400,000
2018 Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Convertible Subordinated Debt	86,300,000	86,300,000
Debt Instrument, Interest Rate, Stated Percentage	3.00%	3.00%
Debt Instrument, Convertible, Conversion Ratio	30.9478
Debt Instrument Convertible Principal Amount Used In Conversion Rate Calculation	$ 1,000	$ 1,000
Debt Instrument, Convertible, Conversion Price	$ 32.31	$ 32.31
Stock Issued During Period, Shares, Other	2,700,000