STOCKHOLDERS' EQUITY (AOCI comp) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Changes in accumulated other comprehensive loss, net of tax, by component
Balances			$ 560,883
Amounts reclassified from accumulated other comprehensive loss			3,281	$ 4,418
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	$ (6,635)	$ (1,917)	(4,106)	(3,788)
Balances	586,795		586,795
Accumulated Other Comprehensive Loss
Changes in accumulated other comprehensive loss, net of tax, by component
Balances			(23,479)	(14,912)
Other comprehensive loss before reclassifications			(7,387)	(8,206)
Amounts reclassified from accumulated other comprehensive loss			3,281	4,418
OTHER COMPREHENSIVE INCOME (LOSS), net of tax			(4,106)	(3,788)
Balances	(27,585)	(18,700)	(27,585)	(18,700)
Unrecognized Net Periodic Benefit Costs
Changes in accumulated other comprehensive loss, net of tax, by component
Balances			(22,387)	(14,386)
Other comprehensive loss before reclassifications			(6,232)	(8,072)
Amounts reclassified from accumulated other comprehensive loss			3,281	4,418
OTHER COMPREHENSIVE INCOME (LOSS), net of tax			(2,951)	(3,654)
Balances	(25,338)	(18,040)	(25,338)	(18,040)
Interest Rate Swap
Changes in accumulated other comprehensive loss, net of tax, by component
Balances			(350)
Other comprehensive loss before reclassifications			(603)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax			(603)
Balances	(953)		(953)
Foreign Currency Translation
Changes in accumulated other comprehensive loss, net of tax, by component
Balances			(742)	(526)
Other comprehensive loss before reclassifications			(552)	(134)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax			(552)	(134)
Balances	$ (1,294)	$ (660)	$ (1,294)	$ (660)