Outstanding Loans and Security Agreements - Schedule of Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2017
Debt Instrument [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
Unused Borrowing Capacity	1,220	1,220
Senior secured notes \| Senior Secured Notes due March 2025, Non-Recourse
Debt Instrument [Line Items]
Unpaid principal balance	76,827	79,698
Current portion of debt	12,151	11,994
Long-term portion of debt	63,635	66,572
Total	$ 75,786	78,566
Interest rate percentage	5.22%
Term loan \| Term Loan due September 2028, Non-Recourse
Debt Instrument [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
Interest rate percentage	7.50%
Term loan \| Senior Secured Notes due October 2020, Non-Recourse
Debt Instrument [Line Items]
Unpaid principal balance	$ 24,438	24,723
Current portion of debt	926	827
Long-term portion of debt	22,808	23,089
Total	$ 23,734	23,916
Interest rate percentage	5.25%
Term loan \| Term Loan due December 2021, Non-Recourse
Debt Instrument [Line Items]
Unpaid principal balance	$ 124,593	125,456
Current portion of debt	3,775	3,672
Long-term portion of debt	118,926	119,712
Total	$ 122,701	123,384
Interest rate percentage	2.50%
Term loan \| Term Loan due November 2020, Recourse
Debt Instrument [Line Items]
Unpaid principal balance	$ 2,857	3,286
Current portion of debt	1,683	1,686
Long-term portion of debt	1,112	1,528
Total	$ 2,795	3,214
Interest rate percentage	4.00%
Non-recourse debt
Debt Instrument [Line Items]
Unpaid principal balance	$ 348,506	353,872
Current portion of debt	21,827	21,162
Long-term portion of debt	317,958	323,360
Total	339,785	344,522
Unused Borrowing Capacity	1,220	1,220
Convertible promissory notes \| Convertible Promissory Notes Interest Rate 5% Due December 2020, Recourse
Debt Instrument [Line Items]
Unpaid principal balance	33,104	33,104
Current portion of debt	0	0
Long-term portion of debt	35,136	34,706
Total	$ 35,136	34,706
Interest rate percentage	5.00%
Convertible promissory notes \| Convertible Promissory Notes Interest Rate 6% Due December 2020, Recourse
Debt Instrument [Line Items]
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
Interest rate percentage	6.00%
Notes \| Notes due July 2024, Recourse
Debt Instrument [Line Items]
Unpaid principal balance	$ 100,000	100,000
Current portion of debt	14,000	7,000
Long-term portion of debt	82,073	88,555
Total	$ 96,073	95,555
Interest rate percentage	10.00%		10.00%
Recourse debt
Debt Instrument [Line Items]
Unpaid principal balance	$ 432,194	432,623
Current portion of debt	15,683	8,686
Long-term portion of debt	385,610	388,073
Total	401,293	396,759
Senior Secured Notes due March 2030, Non-Recourse
Debt Instrument [Line Items]
Unpaid principal balance	82,889	83,457
Current portion of debt	2,634	2,469
Long-term portion of debt	79,172	79,868
Total	$ 81,806	82,337
Interest rate percentage	6.07%
Letters of Credit \| Letter of Credit due December 2021, Non-Recourse
Debt Instrument [Line Items]
Unused Borrowing Capacity	$ 1,220	1,220
Variable Interest Entity, Primary Beneficiary
Debt Instrument [Line Items]
Current portion of debt	21,827	21,162
Long-term portion of debt	$ 317,958	$ 323,360

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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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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