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 Income And Comprehensive Income [Abstract]
Net earnings	$ 160,627	$ 163,067	$ 454,268	$ 440,213
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of tax of $5,803 and $2,904 for the three months ended September 30, 2019 and 2018 and $5,364 and $12,563 for the nine months ended September 30, 2019 and 2018	(14,603)	(10,929)	(14,007)	(28,129)
Reclassification adjustments for foreign currency realized losses, net of tax of $145 for the nine months ended September 30, 2019	0	0	535	0
Other comprehensive loss	(14,603)	(10,929)	(13,472)	(28,129)
Comprehensive income	146,024	152,138	440,796	412,084
Less comprehensive income (loss) attributable to the noncontrolling interest	481	(167)	1,020	230
Comprehensive income attributable to shareholders	$ 145,543	$ 152,305	$ 439,776	$ 411,854