Summary of Significant Accounting Policies - (Additional Information) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016	Jan. 01, 2020
Disaggregation of Revenue [Line Items]
Revenue related to sales-type leases	$ 2,300,000	$ 2,900,000	$ 3,400,000
Revenues	$ 794,247,000	785,177,000	632,648,000
ITC recapture period	5 years
ITC recaptured amount	$ 0	0	0
Operating lease right-of-use assets	35,621,000	0			$ 28,121,000
Operating Lease, Liability	$ 49,748,000
PPA II | PPA Entities
Disaggregation of Revenue [Line Items]
Increase (decrease) in restricted cash		108,700,000
Minimum
Disaggregation of Revenue [Line Items]
Incentives received by the Company				1.00%
Term of PPA	10 years
Term during which the Company is responsible for the installation, operation and maintenance of the Energy Servers	10 years
Minimum | Restricted Stock
Disaggregation of Revenue [Line Items]
Requisite service period	3 years
Minimum | PSUs
Disaggregation of Revenue [Line Items]
Requisite service period	1 year
Maximum
Disaggregation of Revenue [Line Items]
Incentives received by the Company				10.00%
Term of PPA	21 years
Term during which the Company is responsible for the installation, operation and maintenance of the Energy Servers	15 years
Maximum | Restricted Stock
Disaggregation of Revenue [Line Items]
Requisite service period	4 years
Maximum | PSUs
Disaggregation of Revenue [Line Items]
Requisite service period	3 years
Accounting Standards Update 2016-02
Disaggregation of Revenue [Line Items]
Operating lease right-of-use assets		28,100,000
Operating lease, tenant improvement allowance		9,200,000
Operating Lease, Liability		39,800,000
Electricity
Disaggregation of Revenue [Line Items]
Electricity revenue	$ 64,094,000	60,389,000	57,525,000
Revenues	64,094,000	71,229,000	80,548,000
Service
Disaggregation of Revenue [Line Items]
Revenues	109,633,000	95,786,000	83,267,000
Power generation | Electricity sales
Disaggregation of Revenue [Line Items]
Revenues	0	11,300,000	23,000,000.0
Power generation | Service revenue
Disaggregation of Revenue [Line Items]
Revenues	0	6,800,000	13,700,000
Power Purchase Agreement Program Leases | Electricity
Disaggregation of Revenue [Line Items]
Operating Lease, Lease Income	27,700,000	29,700,000	30,900,000
Power Purchase Agreement Program Leases | Service
Disaggregation of Revenue [Line Items]
Operating Lease, Lease Income	$ 13,800,000	$ 14,600,000	$ 15,200,000