Segment Information (Income by Reportable Segments) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Net sales	$ 165,259	$ 160,366	$ 483,314	$ 488,515
Operating income	23,146	23,197	66,002	63,949
Equity income in unconsolidated joint ventures	898	877	2,220	2,187
Other income (expense), net	676	(756)	320	(1,404)
Interest expense, net	(811)	(1,126)	(3,047)	(3,435)
Income before income tax expense	23,909	22,192	65,495	61,297
Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	65,518	66,160	206,115	203,855
Operating income	7,605	12,010	34,334	36,952
Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	54,391	46,783	146,476	138,355
Operating income	10,932	8,150	21,584	16,731
Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	39,777	36,565	113,391	113,633
Operating income	2,767	1,104	4,540	4,372
Other
Segment Reporting Information [Line Items]
Net sales	5,573	10,858	17,332	32,672
Operating income	$ 1,842	$ 1,933	$ 5,544	$ 5,894