Fair Value Measurements - Carrying Value and Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Carrying Value | Level 3
Liabilities:
Non-recourse debt	$ 1,706,921	$ 2,269,421
Carrying Value | Level 3 | Notes Receivable
Assets:
Receivable, fair value	10,351	10,689
Carrying Value | Level 2 | Senior Unsecured Notes
Liabilities:
Non-recourse debt	1,807,200	1,476,084
Fair Value | Level 3
Liabilities:
Non-recourse debt	1,711,364	2,293,542
Fair Value | Level 3 | Notes Receivable
Assets:
Receivable, fair value	10,046	10,610
Fair Value | Level 2 | Senior Unsecured Notes
Liabilities:
Non-recourse debt	$ 1,828,829	$ 1,459,544