Accumulated Other Comprehensive Loss (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reclassification out of AOCI
Sales	$ 103,102	$ 79,783	$ 79,355	$ 67,219	$ 90,560	$ 82,883	$ 86,320	$ 74,650	$ 329,459	$ 334,413	$ 341,573
Other expense									(471)	(559)	(832)
Income from continuing operations before income taxes									5,932	19,341	16,359
Tax (expense) benefit									(1,537)	(1,486)	(4,373)
Net income	6,143	1,479	2,265	40	7,752	4,020	3,640	2,443	9,927	17,855	11,986
Unrealized gain (loss) on cash flow hedges | Amount reclassified from AOCI
Reclassification out of AOCI
Sales									(20)	200
Other expense									14
Income from continuing operations before income taxes									(6)
Tax (expense) benefit									1
Net income									(5)
Retirement plan related adjustment | Amount reclassified from AOCI
Reclassification out of AOCI
Amortization of prior service cost									(647)
Amortization of transition asset									(272)
Amortization of actuarial loss									3,452
Income from continuing operations before income taxes									2,533
Tax (expense) benefit									(221)
Net income									$ 2,312