Note I - Fair Value Measurements - Recurring Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Mar. 31, 2023	Mar. 31, 2022
Derivative assets	$ 3,000	$ 1,600
Fair Value, Recurring [Member]
Derivative assets	292
Total	292
Commodity futures – financial liabilities, net			$ (1,676)
Total			(1,676)
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative assets	292
Total	292
Commodity futures – financial liabilities, net			(1,676)
Total			(1,676)
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative assets	0
Total	0
Commodity futures – financial liabilities, net			0
Total			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Derivative assets	0
Total	$ 0
Commodity futures – financial liabilities, net			0
Total			$ 0