Commitments and Contingencies - Additional Information (Details) $ in Thousands		3 Months Ended		12 Months Ended	109 Months Ended
		Mar. 31, 2021 USD ($) numberOfEmployees	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Mar. 31, 2021 USD ($) numberOfEmployees	Dec. 31, 2020 USD ($) numberOfEmployees	Dec. 31, 2017 USD ($) numberOfEmployees	Sep. 30, 2017 USD ($) numberOfEmployees	Mar. 31, 2012 USD ($)
Operating Leased Assets [Line Items]
Restricted cash, current	[1]	$ 54,865			$ 54,865	$ 52,470
Restricted cash, non-current	[1]	130,080			130,080	117,293
Restricted Cash		184,945			184,945	169,763
Grants receivable									$ 16,500
Number of employees to be hired per incentive grant agreement | numberOfEmployees							900	900
Minimum cumulative employee compensation, recapture period one								$ 108,000
Minimum cumulative employee compensation, recapture period three								$ 324,000
Cumulative compensation expense incurred		162,800			162,800	152,200
Proceeds from government grants					12,000
Grant agreement, maximum possible repayment amount, recapture period two		1,600			1,600
Grant agreement, maximum possible repayment amount, recapture period three		2,500			2,500
Grant agreement, recapture provision repayments							$ 1,500
Delaware grant obligation		9,212			9,212	9,212
Deferred government grant obligation, current		1,300			1,300
PPA Entities
Operating Leased Assets [Line Items]
Restricted cash, current		1,686			1,686	4,698
Restricted cash, non-current		15,367			15,367	15,320
PPA II | PPA Entities
Operating Leased Assets [Line Items]
Restricted cash, current		28,200			28,200	20,300
Restricted cash, non-current		80,500			80,500	88,400
Restricted Cash		108,700			108,700
PPA IIIb | PPA Entities
Operating Leased Assets [Line Items]
Restricted cash, current		1,000			1,000	700
Restricted cash, non-current		$ 13,300			$ 13,300	$ 13,300
Cash and cash equivalents, period increase (decrease)				$ 13,300
Pledged assets, term				7 years
Delaware
Operating Leased Assets [Line Items]
Number of full time employees | numberOfEmployees		462			462	424
PPA V
Operating Leased Assets [Line Items]
PPA expenses		$ 100	$ 5,700

[1] We have variable interest entities, which represent a portion of the consolidated balances recorded within these financial statement line items in the condensed consolidated balance sheets (see Note 11 - Portfolio Financings).