Note H - Derivative Financial Instruments (Details Textual) $ in Thousands	6 Months Ended
	Sep. 30, 2023 USD ($) T	Sep. 30, 2022 USD ($)	Mar. 31, 2023 USD ($)
Derivative Asset	$ 3,000		$ 1,600
Other Current Assets [Member]
Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Not Offset	0		$ 2,400
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Reclassification from AOCI, Current Period, Tax	$ 100	$ 500
Not Designated as Hedging Instrument [Member] | Short [Member]
Derivative, Nonmonetary Notional Amount, Mass (US Ton) | T	22,100