Fair Value - Additional Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) MW	Jun. 30, 2019 USD ($)	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash flow hedge gain to be reclassified within 12 months			$ 2.0
Gain (loss) on derivative	$ 0.4	$ (0.5)	$ (0.7)	$ (1.1)
Measurement Input, Long-term Revenue Growth Rate | Valuation Technique, Option Pricing Model
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Embedded derivative liability, unobservable inputs	0.07		0.07		0.07
Measurement Input, Price Volatility | Valuation Technique, Option Pricing Model
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Embedded derivative liability, unobservable inputs	0.20		0.20		0.20
New Energy Server Systems | PPA IIIb
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of replacement megawatts | MW			0.4
Not designated as hedging instrument | Natural gas forward contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (loss) on derivative	$ (0.1)	(1.1)	$ (0.7)	(0.7)
Gain on the settlement of contracts	$ 1.5	$ 1.1	$ 2.5	$ 1.6