Stock-Based Compensation (Summary of Stock Option Activity) (Details)	9 Months Ended
	Oct. 31, 2015 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning of period, Number of Shares | shares	1,947,928
Granted, Number of Shares | shares	0
Exercised, Number of Shares | shares	(718,628)
Forfeited or expired, Number of Shares | shares	(156,776)
Outstanding at October 31, 2015, Number of Shares | shares	1,072,524
Exercisable at October 31, 2015, Number of Shares | shares	1,072,524
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding, beginning of period, Weighted Average Exercise Price (in dollars per share)	$ 15.16
Granted, Weighted Average Exercise Price (in dollars per share)	0.00
Exercised, Weighted Average Exercise Price (in dollars per share)	11.42
Forfeited or expired, Weighted Average Exercise Price (in dollars per share)	31.31
Outstanding at October 31, 2015, Weighted Average Exercise Price (in dollars per share)	15.31
Exercisable at October 31, 2015, Weighted Average Exercise Price (in dollars per share)	$ 15.31