INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
A reconciliation of the income tax expense with amounts determined by applying the statutory U.S. federal income tax rate to income before income tax expense:
Current income tax payable	$ 2.7	$ 1.1
Deferred income tax liability	$ 21.5	$ 20.9
Texas State Income Tax Rate [Member]
A reconciliation of the income tax expense with amounts determined by applying the statutory U.S. federal income tax rate to income before income tax expense:
Effective income tax rate	0.40%