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, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 21	$ 20	$ 64	$ 60
Interest cost	83	83	247	249
Amortization of actuarial losses	30	36	90	110
Amortization of unrecognized prior service cost (Credit)	(40)	(40)	(120)	(120)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 94	$ 99	$ 281	$ 299