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, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 7	$ 7	$ 14	$ 14
Interest cost	84	79	167	158
Amortization of actuarial losses	24	32	48	64
Amortization of unrecognized prior service cost (Credit)	(40)	(40)	(80)	(80)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 75	$ 78	$ 149	$ 156