Unaudited Quarterly Results (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Net sales:	$ 131,912,000	$ 164,524,000	$ 168,545,000	$ 135,487,000	$ 129,385,000	$ 153,151,000	$ 160,975,000	$ 127,653,000	$ 600,468,000	$ 571,164,000	$ 498,713,000
Segment operating income:	4,142,000	18,640,000	17,585,000	5,353,000	2,370,000	14,563,000	15,127,000	8,143,000	45,720,000	40,203,000	38,401,000
Income from continuing operations before tax and equity investment	2,610,000	17,515,000	15,299,000	3,878,000	1,135,000	12,318,000	14,870,000	(827,000)	39,302,000	27,496,000	23,861,000
Income from discontinued operations, net of tax	1,164,000	2,290,000	3,667,000	2,856,000	1,800,000	3,978,000	3,455,000	11,455,000	9,935,000	5,789,000	12,236,000
Net income	2,604,000	11,860,000	11,076,000	(370,000)	12,499,000	9,643,000	11,872,000	8,015,000	25,170,000	42,029,000	26,481,000
Comprehensive (loss) income	(50,188,000)	10,880,000	11,186,000	(599,000)	54,450,000	7,694,000	12,691,000	11,431,000	(28,721,000)	86,266,000	(11,298,000)
Basic and diluted (loss) income per share of common stock
Income from continuing operations, net of tax (in dollars per share)	$ 0.13	$ 0.77	$ 0.56	$ (0.25)	$ 0.81	$ 0.43	$ 0.62	$ (0.26)	$ 1.23	$ 1.61	$ 1.09
Discontinued operations, net of tax (in dollars per share)	$ 0.11	$ 0.18	$ 0.28	$ 0.22	$ 0.14	$ 0.30	$ 0.26	$ 0.87	$ 0.81	$ 1.56	$ 0.94
Net income per share (in dollars per share)	$ 0.24	$ 0.95	$ 0.84	$ (0.03)	$ 0.95	$ 0.73	$ 0.88	$ 0.61	$ 2.04	$ 3.17	$ 2.03
Other comprehensive income (loss) recorded primarily from unrealized actuarial gain (loss) associated with the Company's defined benefit pension plans	$ 52,800,000				$ (42,000,000)