Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net earnings	$ 58,854	$ 60,438	$ 57,872
Other comprehensive income, net of tax:
Foreign currency translation adjustments	(12,271)	(1,949)	(6,457)
Change in unrealized loss on derivative instruments, net of tax expense of $6, $158, and $161, respectively	9	263	264
Pension plan adjustments, net of tax benefit of $2,412, $7,382, and $23,583, respectively	(3,993)	(12,191)	(38,947)
Other comprehensive income (loss)	(16,255)	(13,877)	(45,140)
Total comprehensive income	$ 42,599	$ 46,561	$ 12,732