Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net earnings	$ 60,438	$ 57,872	$ 57,100
Other comprehensive income, net of tax:
Foreign currency translation adjustments	(1,949)	(6,457)	2,296
Change in unrealized loss on derivative instruments, net of tax benefit (expense) of ($158), ($161), and $38, respectively	263	264	(61)
Pension plan adjustments, net of tax benefit (expense) of $7,382, $23,583, and ($23,933), respectively	(12,191)	(38,947)	38,234
Other comprehensive income (loss)	(13,877)	(45,140)	40,469
Total comprehensive income	$ 46,561	$ 12,732	$ 97,569