CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net earnings	$ 43,003		$ 37,976		$ 60,430
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(5,473)		7,027		(5,294)
Amortization of:
Prior service benefit	0	[1]	0	[1]	(54)
Unrecognized (gain) loss	(268)	[1]	(661)	[1]	763
Unrecognized actuarial gains	247		481		542
Foreign currency exchange rate changes	0		0		3
Income tax related to pension and postretirement plans	9		72		(514)
Pension and postretirement plans, net of tax	(12)		(108)		740
Total other comprehensive income (loss), net of tax	(5,485)		6,919		(4,554)
Comprehensive income	$ 37,518		$ 44,895		$ 55,876

[1] These accumulated other comprehensive income components are included in the computation of net periodic postretirement benefit costs, which are included in other non-operating income (expense), net in our consolidated statements of operations (see Note 17 for additional information).