CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) [Abstract]
Net earnings	$ 17,764	$ 19,244	$ 33,498	$ 31,448
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	2,733	(1,938)	5,456	(153)
Amortization of:
Prior service benefit	0	(14)	0	(27)
Unrecognized loss	(271)	115	(330)	390
Unrecognized actuarial gains	472	301	472	301
Foreign currency exchange rate changes	0	0	0	4
Income tax expense related to pension and postretirement plans	(81)	(164)	(57)	(272)
Pension and postretirement plans, net of tax	120	238	85	396
Total other comprehensive income (loss), net of tax	2,853	(1,700)	5,541	243
Comprehensive income	$ 20,617	$ 17,544	$ 39,039	$ 31,691