Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net earnings	$ 23,824	$ 20,970	$ 76,810	$ 62,526
Currency translation	(590)	262	(632)	(396)
Postretirement plans	55	46	165	140
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	0	0	0	(1,213)
Comprehensive income	$ 23,289	$ 21,278	$ 76,343	$ 61,057