Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Tax credits and net operating loss carryforwards	$ 510,599	$ 494,084
Lease liabilities	128,151	122,145
Depreciation and amortization	7,541	8,523
Deferred revenue	27,134	6,688
Accruals and reserves	15,068	5,874
Stock-based compensation	35,815	61,808
Other items - deferred tax assets	25,931	24,443
Gross deferred tax assets	750,239	723,565
Valuation allowance	(614,958)	(633,591)
Net deferred tax assets	135,281	89,974
Investment in PPA entities	(10,757)	(13,494)
Debt issuance cost	0	(4,055)
Discount upon issuance of debt	(29,513)	0
Managed services - deferred costs	(21,898)	0
Right-of-use assets and leased assets	(70,818)	(65,978)
Other items - deferred tax liability	(1,413)	(5,803)
Gross deferred tax liabilities	(134,399)	(89,330)
Deferred tax assets, net	$ 882	$ 644