VARIABLE INTEREST ENTITIES - Carrying Amounts of Consolidated VIE Assets and Liabilities (Details) $ in Millions	Mar. 31, 2021 USD ($) facility	Dec. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)
Assets
Restricted cash	$ 80.4	$ 54.8	$ 41.5
Loans receivable less allowance for loan losses	658.6	467.5
Prepaid expenses and other	26.8	28.0
Deferred tax assets	1.5	0.0
Total Assets	1,407.6	1,182.9
Liabilities
Accounts payable and accrued liabilities	67.7	49.6
Deferred revenue	5.5	5.4
Accrued interest	5.9	20.1
Debt	1,000.2	819.7
Total Liabilities	$ 1,247.5	1,051.0
Variable Interest Entity
Variable Interest Entity [Line Items]
Number of credit facilities held | facility	3
Assets
Restricted cash	$ 47.6	32.0	$ 22.3
Loans receivable less allowance for loan losses	509.7	306.3
Intercompany receivable	30.2	15.4
Prepaid expenses and other	0.0	0.4
Deferred tax assets	0.1	0.1
Total Assets	587.6	354.2
Liabilities
Accounts payable and accrued liabilities	8.0	34.1
Deferred revenue	0.1	0.1
Accrued interest	1.2	1.1
Debt	319.7	139.6
Total Liabilities	$ 329.0	$ 174.9