Segment Information (Information About Reportable Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Net sales	$ 163,052	$ 142,820	$ 463,187	$ 401,252
Operating income (loss)	28,389	19,009	66,066	37,931
Equity income in unconsolidated joint ventures	953	1,754	2,992	3,045
Other income (expense), net	(107)	(101)	(1,374)	(867)
Interest income (expense), net	(698)	(881)	(2,167)	(2,616)
Income before income tax expense	28,537	19,781	65,517	37,493
Reportable Segment [Member]
Segment Reporting Information [Line Items]
Net sales	163,052	142,820	463,187	401,252
Operating income (loss)	28,389	19,009	66,066	37,931
Equity income in unconsolidated joint ventures	953	1,754	2,992	3,045
Other income (expense), net	(107)	(101)	(1,374)	(867)
Interest income (expense), net	(698)	(881)	(2,167)	(2,616)
Income before income tax expense	28,537	19,781	65,517	37,493
Reportable Segment [Member] | Printed Circuit Materials [Member]
Segment Reporting Information [Line Items]
Net sales	63,353	47,105	183,397	136,253
Operating income (loss)	14,095	5,857	36,355	13,651
Reportable Segment [Member] | High Performance Foams [Member]
Segment Reporting Information [Line Items]
Net sales	46,709	44,460	130,709	126,839
Operating income (loss)	8,442	7,490	18,752	17,622
Reportable Segment [Member] | Power Electronics Solutions [Member]
Segment Reporting Information [Line Items]
Net sales	46,468	45,328	130,185	120,411
Operating income (loss)	3,683	3,810	4,515	823
Reportable Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Net sales	6,522	5,927	18,896	17,749
Operating income (loss)	$ 2,169	$ 1,852	$ 6,444	$ 5,835