Stock-Based Compensation (Schedule Of Stock Options Activity) (Details) (Stock Options [Member])	6 Months Ended
	Jul. 31, 2011
Stock Options [Member]
Outstanding at January 31, 2011	2,881,356
Granted	12,882
Exercised	(1,033,118)
Canceled	(17,774)
Outstanding at July 31, 2011	1,843,346