Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 11,451	$ 25,740	$ 32,158
Other comprehensive income:
Foreign currency translation adjustment	1,552	(172)	(1,335)
Derivative and hedging activity, net of tax benefit (expense) of ($271), ($149), and $1,175,	(1,074)	258	(1,999)
Pension and post-employment benefit adjustment, net of tax benefit (expense) of ($8,870), $4,719, and ($2,963)	(17,234)	(5,562)	4,866
Other comprehensive income (loss)	(16,756)	(5,476)	1,532
Comprehensive income	$ (5,305)	$ 20,264	$ 33,690