Stockholders' Equity Dividends Declared (Details) - $ / shares	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Dividends [Abstract]
Common Stock, Dividends, Per Share, Declared	$ 0.50	$ 0.45	$ 1.45	$ 1.30