INCOME TAXES (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
INCOME TAXES
Income tax benefit at the statutory federal rate (as a percent)	35.00%
State tax, low end of range of rate (as a percent)	6.00%
State tax, high end of range of rate (as a percent)	6.50%
Effective tax benefit rate (as a percent)	42.00%	42.50%
Portion of effective tax benefit rate related to reduced state deferred tax liabilities reflecting enactment of lower tax rates in some states (as a percent)	1.60%
Alternative fuel tax credit, 2012		$ 0.9
Alternative fuel tax credit, 2013		0.3
Refund of federal and state income taxes that were paid in prior years, primarily from loss carrybacks	2.0
Federal, state, and foreign income taxes paid	$ 5.4