Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net earnings	$ 23,411	$ 19,768
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	(6,143)	781
Unrealized gain (loss) on cash flow hedge	512	(3,107)
Change in postretirement benefit plans	7	(579)
Other comprehensive loss	(5,624)	(2,905)
Comprehensive income	$ 17,787	$ 16,863