Summary of Business and Significant Accounting Policies (Concentration of Credit risk) (Details)	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Concentration Risk [Line Items]
Period of Manufacturing Operations	67 years
Sales Revenue, Goods, Net [Member] | Geographic Concentration Risk [Member]
Concentration Risk [Line Items]
Foreign sales revenue by percent	6.30%	6.70%	7.70%