DEBT - Non-Recourse Canada SPV Facility (Details) $ in Thousands, $ in Millions	Sep. 30, 2021 USD ($)	Sep. 30, 2021 CAD ($)	Dec. 31, 2020 USD ($)	Aug. 31, 2018 CAD ($)
Line of Credit Facility [Line Items]
Debt	$ 1,131,998		$ 819,661
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	$ 96,821	$ 96.8	$ 96,075
Deferred financing costs	$ 1,000
Line of Credit | Non-Recourse Canada SPV Facility | Revolving Credit Facility | Canadian Dollar Offered Rate (CDOR)
Line of Credit Facility [Line Items]
Basis spread	6.75%