CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net earnings	$ 166,626	$ 241,686	$ 200,261
Other comprehensive income (loss), net of tax:
Change in minimum liability for pension plans, net of tax effects of $48, $238 and $(27), respectively	102	661	(212)
Fair value adjustment on interest rate swap contracts	(16)	(602)	(735)
Foreign currency translation adjustments	(40,911)	(61,776)	(88,462)
Total other comprehensive loss	(40,825)	(61,717)	(89,409)
Comprehensive income	$ 125,801	$ 179,969	$ 110,852