CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME 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	$ 241,686	$ 200,261	$ 177,015
Other comprehensive income (loss), net of tax:
Pension plans	661	(212)	2,961
Fair value adjustment on interest rate swap contracts	(602)	(735)	1,660
Foreign currency translation adjustments	(61,776)	(88,462)	11,838
Total other comprehensive income (loss)	(61,717)	(89,409)	16,459
Comprehensive income	$ 179,969	$ 110,852	$ 193,474