STOCKHOLDERS' EQUITY (AOCI comp) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Changes in accumulated other comprehensive loss, net of tax, by component
Balances	$ 560,883	$ 520,461	$ 458,999
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(4,017)	(8,567)	42,460
Balances	588,728	560,883	520,461
Accumulated Other Comprehensive Loss
Changes in accumulated other comprehensive loss, net of tax, by component
Balances	(23,479)	(14,912)	(57,372)
Other comprehensive loss before reclassifications	(8,442)	(14,133)
Amounts reclassified from accumulated other comprehensive loss	4,425	5,566
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(4,017)	(8,567)	42,460
Balances	(27,496)	(23,479)	(14,912)
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	(7,535)	(13,567)
Amounts reclassified from accumulated other comprehensive loss	4,425	5,566
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(3,110)	(8,001)
Balances	(25,497)	(22,387)	(14,386)
Interest Rate Swap
Changes in accumulated other comprehensive loss, net of tax, by component
Balances	(350)
Other comprehensive loss before reclassifications	(195)	(350)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(195)	(350)
Balances	(545)	(350)
Foreign Currency Translation
Changes in accumulated other comprehensive loss, net of tax, by component
Balances	(742)	(526)
Other comprehensive loss before reclassifications	(712)	(216)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(712)	(216)
Balances	$ (1,454)	$ (742)	$ (526)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount after tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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