Intangibles (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Finite-Lived Intangible Assets [Line Items]
Total intangible assets amortization expenses	$ 7,000,000	$ 5,500,000	$ 13,700,000	$ 10,700,000
Capitalized Software Development Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Capitalized software development costs	6,100,000	5,900,000	10,100,000	9,800,000
Capitalized computer software amortization	3,500,000	3,300,000	7,100,000	6,600,000
Costs related to stock based compensation	$ 221,000	$ 262,000	$ 400,000	$ 412,000
Useful life (in years)			3 years
Minimum [Member] | Acquired Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)			3 years
Minimum [Member] | Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)			10 years
Maximum [Member] | Acquired Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)			8 years
Maximum [Member] | Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)			17 years