INCOME TAXES (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
INCOME TAXES
Statutory federal tax 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)	36.30%	37.90%
Fuel tax credit (in dollars)	$ 0.5
Refund of federal and state taxes paid in prior years (in dollars)	1.0
Federal, state and foreign income taxes paid (in dollars)	$ 0.8