INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Income tax expense:
Income tax expense (benefit)	$ (3.8)	$ 2.0	$ (1.4)	$ 4.0
Current income tax payable	0.5		0.5		$ 1.5
Deferred income tax liability (Note 15)	17.9		$ 17.9		$ 21.7
Texas State Income Tax Rate [Member]
Income tax expense:
Effective income tax rate (in percentage)			0.40%	0.40%
Reduction in deferred income tax payable	$ (5.4)
State franchise tax rate (in percentage)	0.75%		0.75%		1.00%