CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net earnings	$ 212,584	$ 171,597	$ 282,425
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Change in minimum liability for pension plans (1)	(192)	(58)	(338)
Fair value adjustment on derivative instruments designated as hedges (2)	2,177	(796)	0
Unrealized gain on available-for-sale investments	0	4	0
Foreign currency translation adjustments	5,974	(16,003)	(35,394)
Total other comprehensive income (loss)	7,959	(16,853)	(35,732)
Comprehensive income	$ 220,543	$ 154,744	$ 246,693