Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Deferred tax assets
Accrued vacation and sick leave	$ 1,264	$ 892
Retirement plans	5,448	2,748
Insurance reserves	443	381
Warranty	207	182
Net operating loss carryforwards	3,658	5,303
Right of use liabilities	6,067	0
Inventory	1,175	1,320
Business interest expense limitation	224	540
Other	301	765
Total deferred tax assets	18,787	12,131
Deferred tax liabilities
Tax in excess of book depreciation	(802)	(720)
Right of use assets	(5,519)	0
Other	(53)	(57)
Total deferred tax liabilities	(6,374)	(777)
Valuation allowance	(1,183)	(1,756)
Net long term deferred tax asset	$ 11,230	$ 9,598