Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net earnings	$ 136,200	$ 93,567
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of tax of $5,512 and $4,876 for the three months ended March 31, 2018 and 2017	8,851	8,860
Other comprehensive income	8,851	8,860
Comprehensive income	145,051	102,427
Less comprehensive income attributable to the noncontrolling interest	387	249
Comprehensive income attributable to shareholders	$ 144,664	$ 102,178