Intangible Assets Finite-Lived Intangible Assets by Major Class (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross	$ 171,889	$ 171,889
Accumulated Amortization	(154,314)	(141,567)
Net	17,575	30,322
Amortization of Intangible Assets	$ 12,700	12,900	$ 13,300
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	5 years
Purchased Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	$ 114,754	114,754
Accumulated Amortization	(102,967)	(95,260)
Net	11,787	19,494
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	6,472	6,472
Accumulated Amortization	(6,472)	(6,472)
Net	0	0
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	37,000	37,000
Accumulated Amortization	(34,784)	(30,534)
Net	2,216	6,466
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	11,536	11,536
Accumulated Amortization	(7,964)	(7,174)
Net	3,572	4,362
Order or Production Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	2,127	2,127
Accumulated Amortization	(2,127)	(2,127)
Net	$ 0	$ 0