CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 13,259	$ 28,399
Foreign currency translation adjustment	(6,894)	(4,257)
Pension and other postretirement benefits:
Amortization of loss, net of tax (Note 4)	66	156
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Change in unrealized loss before reclassifications, net of tax (Note 4)	(1,249)	(394)
Unrealized gain reclassified into earnings, net of tax (Note 4)	(67)	(94)
Net current-period other comprehensive income (loss)	(8,144)	(4,589)
Comprehensive income	$ 5,115	$ 23,810

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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