Segment Information (Information About Reportable Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]
Net sales	$ 153,495	$ 132,452	$ 300,135	$ 258,432
Operating income (loss)	16,219	8,107	37,677	18,922
Equity income in unconsolidated joint ventures	1,062	762	2,039	1,291
Other income (expense), net	(76)	(177)	(1,268)	(766)
Interest income (expense), net	(720)	(830)	(1,468)	(1,735)
Income before income tax expense	16,485	7,862	36,980	17,712
Reportable Segment [Member]
Segment Reporting Information [Line Items]
Net sales	153,495	132,452	300,135	258,432
Operating income (loss)	16,219	8,107	37,677	18,922
Equity income in unconsolidated joint ventures	1,062	762	2,039	1,291
Other income (expense), net	(76)	(177)	(1,268)	(766)
Interest income (expense), net	(720)	(830)	(1,468)	(1,735)
Income before income tax expense	16,485	7,862	36,980	17,712
Reportable Segment [Member] | Printed Circuit Materials [Member]
Segment Reporting Information [Line Items]
Net sales	61,507	45,584	120,044	89,148
Operating income (loss)	10,300	3,996	22,260	7,793
Reportable Segment [Member] | High Performance Foams [Member]
Segment Reporting Information [Line Items]
Net sales	42,796	39,933	84,000	82,379
Operating income (loss)	4,580	3,532	10,310	10,132
Reportable Segment [Member] | Power Electronics Solutions [Member]
Segment Reporting Information [Line Items]
Net sales	42,919	40,784	83,717	75,083
Operating income (loss)	(733)	(1,402)	832	(2,987)
Reportable Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Net sales	6,273	6,151	12,374	11,822
Operating income (loss)	$ 2,072	$ 1,981	$ 4,275	$ 3,984