Business Segment and Geographic Information (Information About Reportable Segments) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Net sales	$ 147,724	$ 163,052	$ 153,495	$ 146,640	$ 136,231	$ 142,820	$ 132,452	$ 125,979	$ 610,911	[1]	$ 537,482	[1]	$ 498,761	[1]
Operating income (loss)									80,427		49,280		25,664
Total assets	835,117				806,534				835,117		806,534
Capital expenditures									28,755		16,859		23,774
Depreciation & amortization									26,268		26,351		27,130
Investment in unconsolidated joint ventures	17,214				18,463				17,214		18,463
Equity income in unconsolidated joint ventures									4,123		4,326		4,743
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									610,911		537,482		498,761
Operating income (loss)									80,427		49,280		25,664
Total assets	835,117				806,534				835,117		806,534		759,278
Capital expenditures									28,755		16,859		23,774
Depreciation & amortization									26,268		26,351		27,130
Investment in unconsolidated joint ventures	17,214				18,463				17,214		18,463		21,171
Equity income in unconsolidated joint ventures									4,123		4,326		4,743
Operating Segments [Member] | High Performance Foams [Member]
Segment Reporting Information [Line Items]
Net sales									173,671		168,082		179,421
Operating income (loss)									23,143		22,339		25,730
Total assets	219,502				221,848				219,502		221,848		233,401
Capital expenditures									6,197		3,030		4,947
Depreciation & amortization									6,561		6,410		7,947
Investment in unconsolidated joint ventures	17,214				18,463				17,214		18,463		21,171
Equity income in unconsolidated joint ventures									4,123		4,326		4,743
Operating Segments [Member] | Advanced Connectivity Solutions [Member]
Segment Reporting Information [Line Items]
Net sales									240,864		184,949		161,893
Operating income (loss)									43,703		18,788		8,170
Total assets	215,077				177,716				215,077		177,716		156,103
Capital expenditures									14,290		7,793		12,849
Depreciation & amortization									9,575		7,004		7,172
Operating Segments [Member] | Power Electronics Solutions [Member]
Segment Reporting Information [Line Items]
Net sales									171,832		160,730		134,279
Operating income (loss)									5,355		1,088		(12,022)
Total assets	375,686				382,818				375,686		382,818		345,013
Capital expenditures									7,489		5,287		5,746
Depreciation & amortization									9,332		12,406		11,083
Investment in unconsolidated joint ventures	0				0				0		0		0
Equity income in unconsolidated joint ventures									0		0		0
Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Net sales									24,544		23,721		23,168
Operating income (loss)									8,226		7,065		3,786
Total assets	24,852				24,152				24,852		24,152		24,761
Capital expenditures									779		749		232
Depreciation & amortization									$ 800		$ 531		$ 928

[1] Net sales are allocated to countries based on the location of the customer.