Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Debt Instrument [Line Items]
Short-term debt	$ 82,801	$ 2,166	$ 451
Long-term debt
Total current maturities of long-term debt	26,989	76,415	76,757
Total long-term debt, less current maturities	413,561	298,638	289,448
Nonrecourse
Long-term debt
Total current maturities of long-term debt	0	0	0
Total long-term debt, less current maturities	0	0	0
Recourse
Debt Instrument [Line Items]
Short-term debt	82,801	2,166	451
Long-term debt
Total current maturities of long-term debt	26,989	76,415	76,757
Total long-term debt, less current maturities	$ 413,561	$ 298,638	$ 289,448