Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net income	$ 36,094	$ 28,903	$ 32,687
Other comprehensive income (loss):
Foreign currency translation adjustment	479	4,445	(2,788)
Unrealized gains on derivative instruments	0	0	144
Net gain (loss) on pension and other postretirement benefits	6,706	(574)	(6,533)
Other comprehensive income (loss) before income tax expense (benefit)	7,185	3,871	(9,177)
Income tax expense (benefit) related to items of other comprehensive income (loss)	(2,516)	121	2,021
Other comprehensive income (loss)	4,669	3,992	(7,156)
Comprehensive income	$ 40,763	$ 32,895	$ 25,531