Related Party Transactions - Debt to Related Parties (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Unpaid principal balance	$ 780,700	$ 786,495
Current portion of debt	37,510	29,848
Long-term portion of debt	703,568	711,433
Total	741,078	741,281
Affiliated entity
Related Party Transaction [Line Items]
Unpaid principal balance	67,493	68,272
Current portion of debt	2,341	2,200
Long-term portion of debt	61,151	61,853
Total	$ 63,492	64,053
Convertible Promissory Notes Interest Rate 6% Due December 2020, Recourse \| Convertible promissory notes
Related Party Transaction [Line Items]
Interest rate percentage	6.00%
Unpaid principal balance	$ 296,233	290,400
Current portion of debt	0	0
Long-term portion of debt	267,289	263,284
Total	267,289	263,284
Convertible Promissory Notes Interest Rate 6% Due December 2020, Recourse \| Convertible promissory notes \| Affiliated entity
Related Party Transaction [Line Items]
Unpaid principal balance	27,734	27,734
Current portion of debt	0	0
Long-term portion of debt	27,734	27,734
Total	$ 27,734	27,734
Term Loan due September 2028, Non-Recourse \| Term loan
Related Party Transaction [Line Items]
Interest rate percentage	7.50%
Unpaid principal balance	$ 39,759	40,538
Current portion of debt	2,341	2,200
Long-term portion of debt	33,417	34,119
Total	35,758	36,319
Term Loan due September 2028, Non-Recourse \| Term loan \| Affiliated entity
Related Party Transaction [Line Items]
Unpaid principal balance	39,759	40,538
Current portion of debt	2,341	2,200
Long-term portion of debt	33,417	34,119
Total	$ 35,758	$ 36,319

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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