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, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 7	$ 21	$ 21	$ 64
Interest cost	79	83	237	247
Amortization of actuarial losses	32	30	96	90
Amortization of unrecognized prior service cost (Credit)	(40)	(40)	(120)	(120)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 78	$ 94	$ 234	$ 281