Interim Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 12,989	$ 20,667	$ 28,517	$ 35,920
Other comprehensive income (loss):
Foreign currency translation adjustment	5,604	1,194	(14,850)	1,914
Net gain on pension and other post-retirement benefits	246	215	492	430
Unrealized losses on derivative instruments	(1,144)	(12)	(5,534)	(12)
Other comprehensive income (loss) before income tax expense	4,706	1,397	(19,892)	2,332
Income tax expense related to items of other comprehensive income	(52)	(45)	(104)	(90)
Other comprehensive income (loss)	4,654	1,352	(19,996)	2,242
Comprehensive income	$ 17,643	$ 22,019	$ 8,521	$ 38,162