INCOME TAXES - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) state	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Income Tax Disclosure [Line Items]
Recognized share-based compensation tax benefit	$ 2.5	$ 2.9
Decrease in deferred income tax expense from remeasurement of deferred taxes due to change in tax rate (Tax Cuts and Jobs Act)		21.4
Income tax receivable	1.6	3.4
Reduction in uncertain tax positions from change in enacted tax rate	0.0	1.1
Uncertain tax benefits accrued	2.7	2.7	$ 4.1
Valuation allowance	$ 0.7	0.7
Net change in total valuation allowance		0.3
Number of individual states subject to income taxes | state	50
Minimum [Member]
Income Tax Disclosure [Line Items]
Tax years open to examination	2004
Maximum [Member]
Income Tax Disclosure [Line Items]
Tax years open to examination	2018
Net Operating Loss [Member]
Income Tax Disclosure [Line Items]
Uncertain tax benefits accrued	$ 2.1	2.1
Tax Credit Carryforward [Member]
Income Tax Disclosure [Line Items]
Uncertain tax benefits accrued	$ 0.7	0.7
Alternative Minimum Tax Credit [Member]
Income Tax Disclosure [Line Items]
Tax credits		$ 2.3
Alternative Minimum Tax Credit [Member] | Minimum [Member]
Income Tax Disclosure [Line Items]
Refund tax year	2018
Alternative Minimum Tax Credit [Member] | Maximum [Member]
Income Tax Disclosure [Line Items]
Refund tax year	2020
State Tax Credit [Member]
Income Tax Disclosure [Line Items]
Tax credits	$ 3.6
State and Local Jurisdiction [Member] | Net Operating Loss [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 118.8