Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net earnings	$ 140,357	$ 130,514	$ 267,963	$ 242,445
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments (net of tax of $0 in 2015 and 2014)	3,789	5,386	(15,661)	549
Change in marketable securities (net of tax of $0 in 2015 and 2014)	0	0	0	2
Comprehensive income	$ 144,146	$ 135,900	$ 252,302	$ 242,996