Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net earnings	$ 140,946	$ 108,755	$ 277,146	$ 202,322
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of tax of $15,171 and $5,016 for the three months ended June 30, 2018 and 2017 and $9,660 and $9,892 for the six months ended June 30, 2018 and 2017	(26,051)	9,236	(17,200)	18,096
Other comprehensive (loss) income	(26,051)	9,236	(17,200)	18,096
Comprehensive income	114,895	117,991	259,946	220,418
Less comprehensive income (loss) attributable to the noncontrolling interest	10	(31)	397	218
Comprehensive income attributable to shareholders	$ 114,885	$ 118,022	$ 259,549	$ 220,200