INCOME TAXES - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Income tax holiday expense (benefit)	$ 1.6	$ 1.0	$ (2.4)
Income tax holiday benefit (expense) per share (USD per share)	$ 0.10	$ 0.06	$ (0.14)
Statutory income tax change - benefit	$ 0.0	$ (2.1)	$ 7.6
Change in provisional benefit due to completion of accounting		2.1
Valuation allowances	15.1	9.2
Operating loss carryforwards, foreign	9.9
Operating loss carryforwards, domestic	10.7
Net operating loss (NOL) carryforwards	11.3	8.4
Operating loss carryforwards, valuation allowance	4.7
Unrecognized tax benefits, gross	12.3
Amount excluded from tax provision		0.4
Unrecognized tax benefits	11.3	4.6	6.2	$ 43.0
Unrecognized tax benefit that would impact effective tax rate	11.5
Interest and penalties	0.2	0.2	$ 0.4
Total accrued penalties and interest	1.0	1.1
Net deferred tax liability	(50.3)	(38.0)
Warrants
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits				$ 39.8
State
Operating Loss Carryforwards [Line Items]
Net operating loss (NOL) carryforwards	6.4
Interest Expense Limitation Carryforward
Operating Loss Carryforwards [Line Items]
Valuation allowances	$ 10.4	$ 6.6