INCOME TAXES (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
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%
Net decrease in valuation allowance			$ 400,000	$ 800,000	$ 3,700,000
Alternative fuel tax credit, prior year				900,000
Alternative fuel tax credit, current year				800,000
Reduction in pension liability due to nonunion defined benefit pension plan curtailment		46,300,000
Reduction in net deferred tax assets due to nonunion defined benefit pension plan curtailment		18,000,000
Refund of federal and state taxes				2,200,000
State and foreign income taxes paid				1,200,000
Reconciliation between the effective income tax rate, as computed on income (loss) before income taxes, and the statutory federal income tax rate
Income tax provision (benefit) at the statutory federal rate	7,351,000		4,122,000	1,948,000	(1,637,000)
Federal income tax effects of:
Net reversal in valuation allowances	(550,000)		(396,000)	(766,000)	(3,729,000)
Alternative fuel tax credit	(288,000)		0	(1,708,000)	0
Effect of permanent differences and other	(247,000)		1,121,000	473,000	250,000
State income taxes	756,000		411,000	154,000	243,000
Total income tax provision (benefit)	$ 7,022,000		$ 5,258,000	$ 101,000	$ (4,873,000)
Income tax provision (benefit) at the statutory federal rate (as a percent)	35.00%		35.00%	35.00%	(35.00%)
Federal income tax effects of:
Net reversal in valuation allowances (as a percent)	(2.60%)		(3.40%)	(13.80%)	(79.70%)
Alternative fuel tax credit (as a percent)	(1.40%)		0.00%	(30.70%)	0.00%
Effect of permanent differences and other (as a percent)	(1.20%)		9.50%	8.50%	5.30%
State income taxes (as a percent)	3.60%		3.50%	2.80%	5.20%
Total income tax provision (benefit) (as a percent)	33.40%		44.60%	1.80%	(104.20%)