Intangible Assets Finite-Lived Intangible Assets by Major Class (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 171,889,000	$ 171,889,000
Finite-Lived Intangible Assets, Accumulated Amortization	(128,665,000)	(115,379,000)
Total estimated future amortization expense	43,224,000us-gaap_FiniteLivedIntangibleAssetsNet	56,510,000us-gaap_FiniteLivedIntangibleAssetsNet
Amortization of Intangible Assets	13,300,000us-gaap_AmortizationOfIntangibleAssets	13,800,000us-gaap_AmortizationOfIntangibleAssets	14,800,000us-gaap_AmortizationOfIntangibleAssets
Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	1 year
Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	8 years
Purchased Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	114,754,000	114,754,000
Finite-Lived Intangible Assets, Accumulated Amortization	(87,398,000)	(79,189,000)
Total estimated future amortization expense	27,356,000	35,565,000
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	6,472,000	6,472,000
Finite-Lived Intangible Assets, Accumulated Amortization	(6,472,000)	(6,472,000)
Total estimated future amortization expense	0	0
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	37,000,000	37,000,000
Finite-Lived Intangible Assets, Accumulated Amortization	(26,284,000)	(21,997,000)
Total estimated future amortization expense	10,716,000	15,003,000
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	11,536,000	11,536,000
Finite-Lived Intangible Assets, Accumulated Amortization	(6,384,000)	(5,594,000)
Total estimated future amortization expense	5,152,000	5,942,000
Order or Production Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	2,127,000	2,127,000
Finite-Lived Intangible Assets, Accumulated Amortization	(2,127,000)	(2,127,000)
Total estimated future amortization expense	$ 0	$ 0

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

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-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

Reference 3: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Topic 350

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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