INCOME TAXES, Income Tax Reform (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Line Items]
Tax provision computed at the federal statutory rate, percentage			35.00%	35.00%	35.00%
Untaxed accumulated earnings	$ 199.9		$ 199.9
Income tax rate on illiquid assets			8.00%
Income tax rate on liquid assets			15.50%
Estimated transition tax	17.5
Estimated transition tax, after tax credits	16.0
Number of years of transition tax payable			8 years
Transition tax, interest free, payable in first five year			8.00%
Transition tax, interest free, payable in sixth year			15.00%
Transition tax, interest free, payable in seventh year			20.00%
Transition tax, interest free, payable in eighth year			25.00%
Decrease related to deferred tax assets	$ 2.0		$ 6.3
Decrease related to deferred tax liabilities			4.2
Net adjustment to deferred income tax expense			$ 2.1
Plan [Member]
Income Tax Disclosure [Line Items]
Tax provision computed at the federal statutory rate, percentage		21.00%