Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net earnings	$ 8,792	$ 8,327	$ 26,182	$ 20,455
Other comprehensive income (loss):
Foreign currency translation adjustment	106	(170)	395	(330)
Pension and postretirement benefits, net of tax	401	123	591	362
Comprehensive income	$ 9,299	$ 8,280	$ 27,168	$ 20,487