Retirement Plans (Narrative) (Details) - United States [Member] - USD ($)	3 Months Ended
Apr. 30, 2020	Apr. 30, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Maximum annual contributions per employee, percent	75.00%
Number of common shares held	763,586	673,964
Contributions by employer	$ 210,000	$ 187,000
Minimum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Annual contributions per employee, percent	1.00%

Amount of contribution received by defined benefit plan from employer which increases plan assets.

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-Publisher FASB
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Name:	us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration