STOCKHOLDERS' EQUITY (AOCI comp) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Changes in accumulated other comprehensive income (loss), net of tax, by component
Balances	$ 763,043	$ 717,682
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(2,467)	1,850
Balances	759,206	721,755
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss), net of tax, by component
Balances	203	(14,238)
Other comprehensive income (loss) before reclassifications	(2,425)	554
Amounts reclassified from accumulated other comprehensive income (loss)	(42)	1,296
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(2,467)	1,850
Balances	(2,264)	(12,388)
Unrecognized Net Periodic Benefit Credit (cost)
Changes in accumulated other comprehensive income (loss), net of tax, by component
Balances	2,152	(12,749)
Other comprehensive income (loss) before reclassifications	(8)	661
Amounts reclassified from accumulated other comprehensive income (loss)	(42)	1,296
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(50)	1,957
Balances	2,102	(10,792)
Interest Rate Swap
Changes in accumulated other comprehensive income (loss), net of tax, by component
Balances	(416)	591
Other comprehensive income (loss) before reclassifications	(997)	(332)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(997)	(332)
Balances	(1,413)	259
Foreign Currency Translation
Changes in accumulated other comprehensive income (loss), net of tax, by component
Balances	(1,533)	(2,080)
Other comprehensive income (loss) before reclassifications	(1,420)	225
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(1,420)	225
Balances	$ (2,953)	$ (1,855)

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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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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