CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net earnings	$ 43,029	$ 51,450	$ 41,353
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(3,781)	(1,101)	1,585
Amortization of:
Prior service benefit	(3,017)	(4,317)	(4,784)
Unrecognized loss	2,435	3,123	3,096
Unrecognized amounts	(413)	(343)	33
Foreign currency exchange rate changes	(34)	(32)	14
Income tax benefit (expense) related to pension and postretirement plans	372	577	636
Pension and post retirement plans, net of tax	(657)	(992)	(1,005)
Total other comprehensive income (loss), net of tax	(4,438)	(2,093)	580
Comprehensive income	$ 38,591	$ 49,357	$ 41,933