Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Deferred tax assets
Accrued vacation and sick leave	$ 892	$ 1,015
Retirement plans	2,748	3,756
Insurance reserves	381	451
Warranty	182	242
Net operating loss carryforwards	5,303	4,722
Inventory	1,320	1,085
§ 163 (j) Limitation	540	0
Other	765	624
Total deferred tax assets	12,131	11,895
Deferred tax liabilities
Tax in excess of book depreciation	(720)	(811)
Other	(57)	(66)
Total deferred tax liabilities	(777)	(877)
Valuation allowance	(1,756)	(925)
Net long term deferred tax asset	$ 9,598	$ 10,093