Taxes (Schedule of Income Tax Rate) (Details)	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Taxes [Abstract]
U.S. statutory tax rate	21.00%	33.80%	35.00%
U.S. state income taxes, net of federal income tax benefit	3.30%	1.80%	1.70%
Transition tax on accumulated foreign earnings	3.60%	12.30%	0.00%
Deferred tax benefit from change in tax rate	(0.70%)	(14.10%)	0.00%
Income taxed outside the U.S.	(3.50%)	(6.30%)	(4.50%)
Effective Income Tax Rate Reconciliation, Disposition, Percent	6.70%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent	6.40%	2.10%	0.00%
Net impact of repatriated international earnings	0.80%	(0.10%)	(1.00%)
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	(1.20%)	(0.90%)	(0.60%)
Other, net	1.00%	1.80%	(0.30%)
Effective income tax rate	37.40%	30.40%	30.30%