Consolidated Statement Of Shareholders' Equity (Parenthetical) - $ / shares		3 Months Ended		9 Months Ended
	Feb. 21, 2017	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Statement of Stockholders' Equity [Abstract]
Dividends declared per common share	$ 2.04	$ 0.00	$ 0.00	$ 2.04	$ 2.00