Composition of Certain Financial Statement Captions (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Inventory Disclosure [Abstract]
Raw Materials	$ 8,994	$ 8,533
Work-in-process	82,606	65,645
Finished goods	44,336	43,095
Total inventory	135,936	117,273
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	437,697	428,562
Less accumulated depreciation and amortization	(193,651)	(185,186)
Property, plant and equipment, net, Total	244,046	243,376
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	127,646	127,416
Accumulated amortization	28,023	26,726
Intangible Assets, Net	99,623	100,690
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Intangible assets 2012	7,479
Intangible assets 2013	6,381
Intangible assets 2014	8,412
Intangible assets 2015	10,745
Intangible assets 2016	13,209
Goodwill [Roll Forward]
Goodwill, Translation and Purchase Accounting Adjustments, Total	265
Goodwill, Gross, Beginning Balance	54,820	54,555
Accumulated impairment losses	(11,629)	(11,629)
Goodwill, Net	43,191	42,926
Advanced Ceramic Operations [Member]
Goodwill [Roll Forward]
Goodwill, Translation and Purchase Accounting Adjustments, Total	0
Goodwill, Gross, Beginning Balance	13,108	13,108
Accumulated impairment losses	(7,797)	(7,797)
Goodwill, Net	5,311	5,311
Thermo Materials [Member]
Goodwill [Roll Forward]
Goodwill, Translation and Purchase Accounting Adjustments, Total	0
Goodwill, Gross, Beginning Balance	10,331	10,331
Accumulated impairment losses	0	0
Goodwill, Net	10,331	10,331
ESK Ceramics [Member]
Goodwill [Roll Forward]
Goodwill, Translation and Purchase Accounting Adjustments, Total	265
Goodwill, Gross, Beginning Balance	9,298	9,033
Accumulated impairment losses	0	0
Goodwill, Net	9,298	9,033
Boron [Member]
Goodwill [Roll Forward]
Goodwill, Translation and Purchase Accounting Adjustments, Total	0
Goodwill, Gross, Beginning Balance	22,083	22,083
Accumulated impairment losses	(3,832)	(3,832)
Goodwill, Net	18,251	18,251
Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	1,824	1,808
Accumulated amortization	1,824	1,808
Intangible Assets, Net	0	0
Backlog [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years or months)	1 month
Backlog [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years or months)	3 months
Developed technology [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	70,739	70,590
Accumulated amortization	7,758	7,233
Intangible Assets, Net	62,981	63,357
Developed technology [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years or months)	10 years
Developed technology [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years or months)	20 years
Trade name [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	4,110	4,110
Accumulated amortization	722	698
Intangible Assets, Net	3,388	3,412
Trade name [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years or months)	10 years
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	47,604	47,604
Accumulated amortization	16,944	16,212
Intangible Assets, Net	30,660	31,392
Customer relationships [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years or months)	10 years
Customer relationships [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years or months)	12 years 6 months
Noncompete agreement [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	1,100	1,100
Accumulated amortization	775	775
Intangible Assets, Net	325	325
Noncompete agreement [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years or months)	15 months
Non-amortizing tradename [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	2,269	2,204
Accumulated amortization	0	0
Intangible Assets, Net	2,269	2,204
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	18,811	18,550
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	119,519	117,961
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	237,957	233,702
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	8,514	8,482
Office equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	38,762	37,906
Construction in progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 14,134	$ 11,961