Employee Postretirement Benefits Employee Postretirement Benefits (Details) - Other Postretirement Benefit Plans, Defined Benefit [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 9	$ 7	$ 18	$ 14
Interest cost	70	84	140	167
Amortization of actuarial losses	43	24	86	48
Amortization of unrecognized prior service cost (Credit)	(40)	(40)	(80)	(80)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 82	$ 75	$ 164	$ 149