Intangibles (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Finite-Lived Intangible Assets [Line Items]
Total intangible assets amortization expenses	$ 28,100,000	$ 25,500,000	$ 17,900,000
Useful life (in years)	5 years
Capitalized Software Development Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Capitalized software development costs	12,200,000	12,600,000	16,500,000
Capitalized computer software amortization	14,100,000	13,400,000	10,700,000
Costs related to stock based compensation	$ 519,000	$ 539,000	$ 719,000
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	9 months
Weighted Average [Member] | Capitalized Software Development Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	1 year 6 months
Weighted Average [Member] | Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	4 years
Weighted Average [Member] | Acquired Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	2 years 6 months
Weighted Average [Member] | Other [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	2 years