Employee Postretirement Benefits Employee Postretirement Benefits (Details) - Other Postretirement Benefit Plans, Defined Benefit [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 9	$ 7	$ 27	$ 21
Interest cost	70	83	210	250
Amortization of actuarial losses	43	24	129	72
Amortization of unrecognized prior service cost (Credit)	(40)	(40)	(120)	(120)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 82	$ 74	$ 246	$ 223