Power Purchase Agreement Programs - Schedule of Consolidated Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Current assets	$ 490,359	$ 672,581
Long-term assets	679,568	717,087
Total assets	1,169,927	1,389,668
Current liabilities	266,565	249,818
Current portion of debt	27,161	29,848
Long-term liabilities	250,477	307,859
Long-term portion of debt	636,808	711,433
Total liabilities	1,181,011	1,298,958
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Current assets	23,077	26,231
Long-term assets	507,357	496,688
Total assets	530,434	522,919
Current liabilities	15,575	2,952
Current portion of debt	11,483	21,162
Long-term liabilities	20,978	14,120
Long-term portion of debt	249,115	323,360
Total liabilities	297,151	361,594
Bloom
Variable Interest Entity [Line Items]
Current assets	467,282	646,350
Long-term assets	172,211	220,399
Total assets	639,493	866,749
Current liabilities	250,990	246,866
Current portion of debt	15,678	8,686
Long-term liabilities	229,499	293,739
Long-term portion of debt	387,693	388,073
Total liabilities	$ 883,860	$ 937,364