Debt Senior Notes (Details) (USD $)	3 Months Ended	12 Months Ended		24 Months Ended			3 Months Ended		3 Months Ended
	Mar. 31, 2014	Nov. 14, 2016	Nov. 14, 2015	Nov. 15, 2018	Mar. 31, 2014 2018 Senior Notes [Member]	Dec. 31, 2013 2018 Senior Notes [Member]	Mar. 31, 2014 2017 Convertible Senior Notes [Member]	Dec. 31, 2013 2017 Convertible Senior Notes [Member]	Mar. 31, 2014 2018 Convertible Senior Notes [Member]	Dec. 31, 2013 2018 Convertible Senior Notes [Member]	Mar. 31, 2014 Face Value [Member] 2018 Senior Notes [Member]	May 08, 2012 Face Value [Member] 2018 Senior Notes [Member]	Nov. 12, 2010 Face Value [Member] 2018 Senior Notes [Member]
Debt Instrument [Line Items]
Convertible senior subordinated notes							$ 57,500,000	$ 57,500,000	$ 86,250,000	$ 86,250,000
Debt Instrument, Interest Rate, Stated Percentage					8.625%		3.25%		3.00%
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		102.20%	104.30%	100.00%
Debt Instrument, Convertible, Conversion Ratio							42.0159		30.9478
Debt Instrument Convertible Principal Amount Used In Conversion Rate Calculation							1,000		1,000
Debt Instrument, Convertible, Conversion Price							$ 23.80		$ 32.31
Stock Issued During Period, Shares, Other							2,400,000		2,700,000
Senior notes					228,169,000	228,070,000					230,000,000	30,000,000	200,000,000
Preferred Stock, Dividend Rate, Percentage	9.75%
Restricted Payments Basket	136,400,000
Preferred shares redeemed during period	2,000
Redemption of preferred shares	50,352,000
Dividends, Preferred Stock	$ (1,219,000)