Note M - Subsequent Events (Details Textual) - Wells Fargo Bank, N.A. [Member] - Credit Agreement [Member] - USD ($) $ in Millions	Feb. 13, 2024	Aug. 18, 2021	Dec. 31, 2023	Jun. 30, 2022	Jun. 30, 2021	May 24, 2021
Line of Credit Facility, Maximum Borrowing Capacity						$ 20.0
Debt Instrument Covenant Capital Expenditures Limitation, Amount, Next Twelve Years				$ 15.0	$ 10.0
Maximum [Member]
Debt Instrument Covenant Capital Expenditures Limitation, Amount, Next Twelve Years			$ 7.5
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Debt Instrument, Basis Spread on Variable Rate		1.29%
Subsequent Event [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 12.5
Subsequent Event [Member] | Maximum [Member]
Debt Instrument Covenant Capital Expenditures Limitation, Amount, Next Twelve Years	7.5
Subsequent Event [Member] | Minimum [Member]
Debt Instrument Covenant Capital Expenditures Limitation, Amount, Next Twelve Years	$ 6.5
Subsequent Event [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	2.25%