Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Net sales	$ 272,858	$ 281,050	$ 292,905
Operating costs and expenses:
Costs of products sold (excluding depreciation)	218,597	217,342	225,906
Selling and administrative	37,380	39,682	40,530
Depreciation	11,818	11,342	10,661
Charge (credit) for asbestos litigation	4,487	(16,340)	(540)
Loss on disposition of assets	496	57	56
Total operating expenses	272,778	252,083	276,613
Income from operations	80	28,967	16,292
Other income (expense):
Investment-related income	171	89	63
Interest expense	(236)	(245)	(246)
Other - net	(907)	(1,631)	(942)
Total other income (expense)	(972)	(1,787)	(1,125)
(Loss) income before income taxes and equity losses in Chinese joint venture	(892)	27,180	15,167
Income tax benefit (provision)	766	(5,813)	(5,218)
Equity losses in Chinese joint venture (including an impairment charge of $6,407 in 2013)	(1,061)	(8,930)	(1,594)
Net (loss) income	$ (1,187)	$ 12,437	$ 8,355
Net (loss) income per common share:
Basic	$ (0.11)	$ 1.20	$ 0.81
Diluted	$ (0.11)	$ 1.20	$ 0.80
Weighted average number of common shares outstanding:
Basic	10,405,000	10,358,000	10,338,000
Diluted	10,404,744	10,406,478	10,389,678