CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014
Income Statement [Abstract]
Net sales	$ 131,240	$ 134,227	$ 393,107	[1]	$ 408,246	[2]
Cost of sales	99,549	105,663	299,827		318,830
Gross profit	31,691	28,564	93,280		89,416
Selling, product development and administrative expenses	16,850	22,785	51,332		63,438
Operating income	14,841	5,779	41,948	[1]	25,978	[2]
Gain on sale of business			(18,647)		0
Interest expense	187	327	595		819
Other income, net	(150)	(508)	(619)		(154)
Income before income taxes	14,804	5,960	60,619		25,313
Income tax expense	3,618	1,802	19,679		9,199
Net income	$ 11,186	$ 4,158	$ 40,940		$ 16,114
Earnings per share:
Basic (usd per share)	$ 0.67	$ 0.25	$ 2.45		$ 0.97
Diluted (usd per share)	$ 0.66	$ 0.24	$ 2.40		$ 0.95
Weighted average number of common shares outstanding:
Basic (in shares)	16,715	16,684	16,744		16,615
Diluted (in shares)	17,028	17,043	17,085		16,967

[1] Other Products and Services reports results for the period preceding the date of disposition of January 30, 2015.

[2] Industrial Filtration segment reports results for the period following the date of acquisition of February 20, 2014 through September 30, 2014.