Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended	12 Months Ended
	Jan. 15, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Interest expense		$ 29,580	$ 39,497	$ 36,384
Principal amount repurchased		152,500	0	0
Accelerated amortization of debt issuance costs and discount		28,240	0	0
Senior Notes
Debt Instrument [Line Items]
Interest expense		28,687	18,084	14,980
Accrued interest		1,523	1,720
Debt issuance costs		375	223	266
Junior subordinated debt
Debt Instrument [Line Items]
Interest expense		893	21,413	21,404
Accrued interest		0	4,448
Principal amount repurchased	152,500
Accelerated amortization of debt issuance costs and discount	$ 28,240