INCOME TAXES (Details 2) (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
Deferred tax assets:
Accrued expenses	$ 51,715				$ 45,970				$ 51,715	$ 45,970
Pension liabilities	34,163				35,529				34,163	35,529
Postretirement liabilities other than pensions	7,127				6,701				7,127	6,701
Share-based compensation	6,034				7,138				6,034	7,138
Federal and state net operating loss carryovers	14,071				3,799				14,071	3,799
Other	2,092				1,223				2,092	1,223
Total deferred tax assets	115,202				100,360				115,202	100,360
Valuation allowance	(2,511)				(5,644)				(2,511)	(5,644)
Total deferred tax assets, net of valuation allowance	112,691				94,716				112,691	94,716
Deferred tax liabilities:
Amortization, depreciation, and basis differences for property, plant and equipment and other long-lived assets	73,558				71,755				73,558	71,755
Intangibles	37,282				954				37,282	954
Revenue recognition	4,268				3,013				4,268	3,013
Prepaid expenses	3,647				3,368				3,647	3,368
Total deferred tax liabilities	118,755				79,090				118,755	79,090
Net deferred tax assets (liabilities)	(6,064)				15,626				(6,064)	15,626
Reconciliation between the effective income tax rate, as computed on income or loss before income taxes, and the statutory federal income tax rate
Income tax provision (benefit) at the statutory federal rate									(5,947)	3,323	(18,829)
Federal income tax effects of:
State income taxes									352	(316)	976
Nondeductible expenses									1,415	1,079	1,179
Life insurance proceeds and changes in cash surrender value									(752)	(906)	(882)
Dividends received deduction									(5)		(14)
Alternative fuel credit										(995)	(979)
Decrease in valuation allowances									(3,180)	(211)	(558)
Other									(539)	(182)	520
Federal income tax provision (benefit)									(8,656)	1,792	(18,587)
State income tax provision (benefit)									(1,005)	902	(3,047)
Foreign income tax provision									401	466	258
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)
Effective tax (benefit) rate (as a percent)									(54.50%)	33.30%	(39.70%)