Shareholders' Equity (Narrative) (Details) - $ / shares shares in Millions	3 Months Ended						12 Months Ended
	Jul. 31, 2015	Jan. 31, 2015	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2015
Class of Stock [Line Items]
Acquirement minimum of outstanding common stock							15.00%
Redeemable value per each right							$ 0.001
Common stock authorized for repurchase	14.0						14.0
Shares with remaining authorization for repurchase under stock repurchase plan	13.0						13.0
Cash dividend declared per common share	$ .34	$ .33	$ 0.165	$ 0.165	$ 0.140	$ 0.140
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, price per one one-thousandth preferred share	$ 143.00						$ 143.00