Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net earnings	$ 459,497	$ 379,460	$ 350,011
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of tax of $23,801 in 2015, $17,348 in 2014 and $6,574 in 2013	(44,090)	(32,080)	(12,420)
Reclassification adjustments for foreign currency realized losses, net of tax of $61 in 2014	0	111	0
Other comprehensive loss	(44,090)	(31,969)	(12,420)
Comprehensive income	415,407	347,491	337,591
Less comprehensive income attributable to the noncontrolling interest	1,605	2,155	1,064
Comprehensive income attributable to shareholders	$ 413,802	$ 345,336	$ 336,527