Unaudited Quarterly Results (Details) (USD $)	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
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 152,309,000	$ 171,874,000	$ 182,084,000	$ 148,957,000	$ 126,084,000	$ 144,628,000	$ 164,430,000	$ 144,386,000	$ 655,224,000	$ 579,528,000	$ 579,764,000
Segment operating income:	5,536,000	16,249,000	17,964,000	11,201,000	7,056,000	12,855,000	19,397,000	10,482,000	50,950,000	49,790,000	45,538,000
Income from continuing operations before tax and equity investment	4,278,000	14,004,000	17,687,000	2,180,000	3,818,000	7,331,000	16,546,000	7,519,000	38,149,000	35,214,000	28,328,000
(Loss) income from discontinued operations, net of tax	(204,000)	2,904,000	1,661,000	9,541,000	1,312,000	1,205,000	1,230,000	585,000	(997,000)	4,311,000	1,678,000
Net income	12,497,000	9,643,000	11,872,000	8,017,000	4,503,000	5,930,000	10,952,000	5,096,000	42,029,000	26,481,000	138,775,000
Comprehensive income (loss)	54,450,000	7,694,000	12,691,000	11,431,000	(27,411,000)	9,551,000	1,617,000	4,945,000	86,266,000	(11,298,000)	86,251,000
Basic and diluted income per share of common stock
Income from continuing operations, net of tax, per share	$ 0.96	$ 0.51	$ 0.76	$ (0.11)	$ 0.24	$ 0.36	$ 0.74	$ 0.35	$ 2.12	$ 1.70	$ 10.71
Discontinued operations, net of tax, per share	$ (0.01)	$ 0.22	$ 0.12	$ 0.72	$ 0.10	$ 0.09	$ 0.09	$ 0.05	$ 1.05	$ 0.33	$ 0.34
Net income per share	$ 0.95	$ 0.73	$ 0.88	$ 0.61	$ 0.34	$ 0.45	$ 0.83	$ 0.40	$ 3.17	$ 2.03	$ 11.05
Other comprehensive income (loss) recorded primarily from unrealized actuarial gain (loss) associated with the Company's defined benefit pension plans	$ 41,800,000				$ (29,200,000)