Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 73,486	$ 44,315	$ 40,045
Other comprehensive (loss) income:
Foreign currency translation adjustment	(13,347)	16,966	(13,156)
Net (loss) gain on pension and other post-retirement benefits	(1,667)	987	2,369
Other comprehensive (loss) income before income tax benefit (expense)	(15,014)	17,953	(10,787)
Income tax benefit (expense) related to items of other comprehensive (loss) income	349	(363)	(890)
Other comprehensive (loss) income	(14,665)	17,590	(11,677)
Comprehensive income	$ 58,821	$ 61,905	$ 28,368