GOODWILL AND INTANGIBLES - Definite-Lived Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 5.4	$ 5.4
Accumulated Amortization	4.6	4.4
Net Book Value	$ 0.8	$ 1.0
Weighted avg useful life	4 years 1 month 6 days	5 years 1 month 6 days
Client lists
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2.0	$ 2.0
Accumulated Amortization	1.2	1.0
Net Book Value	$ 0.8	$ 1.0
Weighted avg useful life	4 years 1 month 6 days	5 years 1 month 6 days
Client lists | Minimum Years
Finite-Lived Intangible Assets [Line Items]
Amortization Period (Years)	5 years	5 years
Client lists | Maximum Years
Finite-Lived Intangible Assets [Line Items]
Amortization Period (Years)	10 years	10 years
Domain name
Finite-Lived Intangible Assets [Line Items]
Amortization Period (Years)	5 years	5 years
Gross Carrying Amount	$ 3.4	$ 3.4
Accumulated Amortization	3.4	3.4
Net Book Value	$ 0.0	$ 0.0
Weighted avg useful life	0 years	0 years