Guarantees and Indemnifications Guarantees (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Senior notes	$ 228,769	$ 228,469
Convertible senior subordinated notes due 2017	57,500	57,500
Convertible senior subordinated notes due 2018	86,250	86,250
Total of Loans Covered by Guarantees	18,900	33,400
Total of Guaranteed Loans Inquired About	7,200	9,100
Total Loans Indemnified to third parties	2,200	2,000
Loan Repurchase Guarantee Liability	$ 2,200	$ 2,900
2018 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	8.625%
2017 Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.25%
2018 Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.00%
Face Value [Member]
Debt Instrument [Line Items]
Senior notes	$ 230,000