Stock-Based Compensation (Schedule Of Stock Options Activity) (Details) (Stock Options [Member])	9 Months Ended
	Oct. 31, 2011
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at January 31, 2011	2,881,356
Granted	12,882
Exercised	(1,116,534)
Canceled	(21,394)
Outstanding at October 31, 2011	1,756,310