Segment Information - Information About Reportable Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting Information [Line Items]
Net sales	$ 130,248	$ 147,344	$ 378,292	$ 426,773
Segment operating income (loss)	10,101	17,923	18,492	47,660
Equity income in unconsolidated joint ventures	1,773	1,290	3,735	4,041
Other income (expense), net	19	302	141	1,931
Net realized investment gain (loss)		(235)	(3,245)	(203)
Interest income (expense), net	(1,104)	(1,040)	(3,366)	(3,884)
Income (loss) before income tax expense (benefit)	10,789	18,240	15,757	49,545
Reportable Segment
Segment Reporting Information [Line Items]
Net sales	130,248	147,344	378,292	426,773
Segment operating income (loss)	10,101	17,923	18,492	47,660
Equity income in unconsolidated joint ventures	1,773	1,290	3,735	4,041
Other income (expense), net	19	302	141	1,931
Net realized investment gain (loss)		(235)	(3,245)	(203)
Interest income (expense), net	(1,104)	(1,040)	(3,366)	(3,884)
Income (loss) before income tax expense (benefit)	10,789	18,240	15,757	49,545
Reportable Segment | High Performance Foams
Segment Reporting Information [Line Items]
Net sales	48,045	49,795	131,807	132,950
Segment operating income (loss)	8,848	10,717	16,001	22,010
Reportable Segment | Printed Circuit Materials
Segment Reporting Information [Line Items]
Net sales	43,437	43,007	123,352	129,235
Segment operating income (loss)	3,195	2,822	5,971	12,056
Reportable Segment | Power Electronics Solutions | Curamik Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	22,050	36,764	70,250	104,274
Segment operating income (loss)	(2,393)	4,133	(5,371)	7,290
Reportable Segment | Power Electronics Solutions | Power Distribution Systems
Segment Reporting Information [Line Items]
Net sales	9,395	11,282	31,484	37,696
Segment operating income (loss)	(326)	342	(840)	4,251
Reportable Segment | Other
Segment Reporting Information [Line Items]
Net sales	7,321	6,496	21,399	22,618
Segment operating income (loss)	$ 777	$ (91)	$ 2,731	$ 2,053