Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Tax credits and NOLs	$ 494,084	$ 468,402
Leased liabilities	122,145	108,113
Depreciation and amortization	8,523	9,631
Deferred revenue	6,688	457
Accruals and reserves	5,874	4,462
Stock-based compensation	61,808	62,793
Other items - DTA	24,443	17,863
Gross deferred tax assets	723,565	671,721
Valuation allowance	(633,591)	(571,277)
Net deferred tax assets	89,974	100,444
Investment in PPA entities	(13,494)	(21,587)
Debt issuance cost	(4,055)	(8,586)
Leased assets	(65,978)	(62,681)
Other items - DTL	(5,803)	(6,817)
Gross deferred tax liabilities	(89,330)	(99,671)
Deferred tax assets, net	$ 644	$ 773