Condensed Consolidated Statements of Comprehensive Income (unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Condensed Consolidated Statements of Comprehensive Income (unaudited) [Abstract]
Net earnings	$ 9,732	$ 11,582	$ 18,626	$ 22,470
Other comprehensive (loss) income, net of tax:
Net foreign currency translation adjustment	(176)	242	(194)	(265)
Net change in postretirement benefit plan, net of taxes of $1 and $-0- for the three months ended June 30, 2014 and 2013, and $2 and $1 for the six months ended June 30, 2014 and 2013	(2)	3	(4)	(2)
Other comprehensive (loss) income	(178)	245	(198)	(267)
Comprehensive income	$ 9,554	$ 11,827	$ 18,428	$ 22,203