Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net earnings	$ 20,676	$ 19,214	$ 59,288	$ 58,239
Other comprehensive (loss) income, net of tax:
Net foreign currency translation adjustment	(2,209)	(545)	(3,513)	(2,093)
Unrealized loss on cash flow hedge, net	(657)	0	(1,956)	0
Net change in postretirement benefit plans	5	9	16	38
Other comprehensive loss	(2,861)	(536)	(5,453)	(2,055)
Comprehensive income	$ 17,815	$ 18,678	$ 53,835	$ 56,184