INCOME TAXES (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
INCOME TAXES
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%
Alternative fuel tax credit	$ 300,000		$ 900,000
Valuation allowance for deferred tax assets		4,700,000
Refund of federal and state taxes	0
State and foreign income taxes paid	500,000
Reconciliation between the effective income tax rate, as computed on loss before income taxes, and the statutory federal income tax rate
Income tax benefit at the statutory federal rate	(8,156,000)	(7,888,000)
Federal income tax effects of:
Increase in valuation allowances	312,000	4,660,000
Alternative fuel tax credit	(1,180,000)
Effect of permanent differences and other	18,000	(235,000)
State income taxes	(902,000)	(911,000)
Total income tax benefit	$ (9,908,000)	$ (4,374,000)
Income tax benefit at the statutory federal rate (as a percent)	(35.00%)	(35.00%)
Federal income tax effects of:
Increase in valuation allowances (as a percent)	1.30%	20.70%
Alternative fuel tax credit (as a percent)	(5.00%)
Effect of permanent differences and other (as a percent)	0.10%	(1.00%)
State income taxes (as a percent)	(3.90%)	(4.10%)
Total income tax benefit (as a percent)	(42.50%)	(19.40%)