COMMITMENTS AND CONTINGENCIES - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Loss Contingencies [Line Items]
Estimated liability, representation and warranties	$ 9.6		$ 9.6
Residential mortgage loan repurchase liability	1,500.0		1,500.0
Rent expense, net of sublease income	3.3	$ 2.4	10.1	$ 6.8
Sublease rentals	1.3		1.3
Unfunded Loan Commitment | Consumer Portfolio Segment | Consumer Loan Companies
Loss Contingencies [Line Items]
Financing receivable	$ 264.2		$ 264.2