Stock-Based Compensation (Schedule Of Stock Options Activity) (Details) (Stock Options [Member])	3 Months Ended
	Apr. 30, 2012
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at January 31, 2012	1,651,400
Granted	6,236
Exercised	(1,000,774)
Canceled	(13,221)
Outstanding at April 30, 2012	643,641