Stockholders' Equity (Share Repurchases) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jan. 31, 2017	Oct. 31, 2016	Dec. 15, 2011
Equity [Abstract]
Share Repurchase Program, maximum amount authorized			$ 500.0
Number of common stock repurchased, shares	0	0
Share Repurchase Program, remaining authorized amount	$ 118.4