DEBT - Non-Recourse Canada SPV Facility (Details) $ in Millions, $ in Millions	1 Months Ended	3 Months Ended
	Apr. 30, 2019	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Aug. 31, 2018 CAD ($)
Line of Credit Facility [Line Items]
Debt		$ 1,000.2	$ 819.7
Line of Credit | Non-Recourse Canada SPV Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				$ 175.0
Credit facility, expansion capacity				$ 250.0
Commitment fee on unused portion		0.50%
Debt instrument, extended term	1 year
Debt		$ 97.3	$ 96.1
Deferred financing costs		$ 1.6
Line of Credit | Non-Recourse Canada SPV Facility | Revolving Credit Facility | Basis Spread Scenario One | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread		6.75%
Line of Credit | Non-Recourse Canada SPV Facility | Revolving Credit Facility | Basis Spread Scenario Two | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread		8.60%