Employee Stock Benefit Plans (Weighted-average Assumptions Of Stock Options Granted) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2011 customers years	Oct. 01, 2010 customers years	Sep. 30, 2011 years employees customers companies	Oct. 01, 2010 years
Expected term	4.9	4.9	4.9	4.9
Stock Options [Member]
Volatility	48.90%	49.30%	43.60%	48.70%
Risk-free interest rate	1.10%	1.80%	1.90%	1.90%