Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net earnings	$ 79,671	$ 78,573	$ 90,071
Other comprehensive (loss)/income, net of tax:
Net foreign currency translation adjustment	(891)	(2,982)	5,404
Unrealized loss on cash flow hedge, net of taxes of $372 at December 31, 2019	(1,399)	0	0
Net change in postretirement benefit plan, net of taxes of $101, $434, and $207 at December 31, 2019, 2018 and 2017, respectively	328	1,022	(197)
Other comprehensive (loss)/income	(1,962)	(1,960)	5,207
Comprehensive income	$ 77,709	$ 76,613	$ 95,278