Interim Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net Income	$ 23,543	$ 16,592	$ 56,897	$ 41,075
Other comprehensive income:
Foreign currency translation adjustments	(924)	7,452	(9,657)	17,596
Net gain on pension and other postretirement benefits	211	218	634	652
Other comprehensive income before income tax expense	(713)	7,670	(9,023)	18,248
Income tax expense related to items of other comprehensive loss	(44)	(80)	(133)	(239)
Other comprehensive income	(757)	7,590	(9,156)	18,009
Comprehensive Income	$ 22,786	$ 24,182	$ 47,741	$ 59,084

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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Amount before tax, after reclassification adjustments of gain (loss) on foreign currency translation adjustments, on foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to parent entity.

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

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Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss) attributable to parent entity.

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