Note 9 - Income Taxes - Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 31, 2021
Future tax credits	$ 5,244	$ 5,884
Inventory valuation	3,098	2,204
Employee benefits	2,191	2,063
Insurance	345	685
Other comprehensive loss	8,975	6,511
Interest	3	4
Prepaid revenue	374	463
Net operating loss and other tax attribute carryovers	610	85
Equity investment basis difference	0	1,589
Other	0	815
Total assets	20,840	20,303
Property basis and depreciation difference	21,807	17,975
Intangibles	17	33
Right of use assets	5,764	4,371
Pension	21,253	21,556
Other	1,012	0
Total liabilities	49,853	43,935
Valuation allowance - noncurrent	3,931	4,674
Net deferred income tax liability	$ (32,944)	$ (28,306)

The tax effect as of the balance sheet date of the amount of estimated future tax deductions related to interest.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from inventory.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount, before allocation of a valuation allowances, of deferred tax assets attributable to deductible tax credit carryforwards including, but not limited to, research, foreign, general business, alternative minimum tax, and other deductible tax credit carryforwards.

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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences from compensation and benefits, classified as other.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.

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Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill.

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Amount of deferred tax liability attributable to taxable temporary differences from leasing arrangements.

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Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment.

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