INCOME TAXES - COMPONENTS OF NET DEFERRED TAX ASSETS (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Income taxes
Balance of future tax benefits	$ 0.0	$ 2.4
Future tax benefits	33.3	0.5
Domestic tax authority
Income taxes
Federal tax credit carryforwards	0.0	0.0
Federal tax credit carryforwards, deferred tax effect	$ 33.3	0.3
State and local jurisdiction
Income taxes
Net operating loss carryforwards		2.4
Net operating loss carryforwards, deferred tax effect		$ 0.2