INCOME TAXES (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current provision (benefit):
Federal										$ (872)	$ (10,756)
State									694	487	549
Foreign									405	489	288
Current provision (benefit)									1,099	104	(9,919)
Deferred provision (benefit):
Federal									(8,656)	2,664	(7,831)
State									(1,699)	415	(3,596)
Foreign									(4)	(23)	(30)
Deferred tax provision (benefit)									(10,359)	3,056	(11,457)
Income tax provision (benefit)	(4,387)	5,258	(5,757)	(4,374)	530	6,808	3,169	(7,346)	(9,260)	3,160	(21,376)
Significant components of the deferred tax provision or benefit
Amortization, depreciation, and basis differences for property, plant and equipment and other long-lived assets									137	15,059	(11,552)
Amortization of intangibles									(1,604)
Changes in reserves for workers' compensation and cargo claims									(3,319)	(970)	1,759
Revenue recognition									(253)	654	1,201
Allowance for doubtful accounts									229	(705)	(428)
Foreign tax credit carryforward									(133)	(240)	286
Nonunion pension and other retirement plans									702	(4,885)	(963)
Deferred compensation plans									669	853	696
Federal net operating loss carryforwards									(2,538)	(680)
State net operating loss carryforwards									(725)	705	(302)
State depreciation adjustments									20	(1,179)	74
Share-based compensation									(702)	(941)	(971)
Valuation allowance decrease									(3,180)	(782)	(558)
Leases									806	(316)	(585)
Other accrued expenses									(1,586)	(863)	629
Other									1,118	(2,654)	(743)
Deferred tax provision (benefit)									$ (10,359)	$ 3,056	$ (11,457)