Note F - Fair Value Measurements - Assets Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Assets, Fair Value Disclosure		$ 17,722
Equity Securities [Member]
Assets, Fair Value Disclosure	$ 22	68
U S Treasury Mutual Fund [Member]
Assets, Fair Value Disclosure	40,138
Equity Mutual Fund [Member]
Assets, Fair Value Disclosure		16,294
Commodity Mutual Fund [Member]
Assets, Fair Value Disclosure		222
Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure		17,722
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Assets, Fair Value Disclosure	22	68
Fair Value, Inputs, Level 1 [Member] | U S Treasury Mutual Fund [Member]
Assets, Fair Value Disclosure	40,138
Fair Value, Inputs, Level 2 [Member] | U S Treasury Mutual Fund [Member]
Assets, Fair Value Disclosure	0
Fair Value, Inputs, Level 2 [Member] | Equity Mutual Fund [Member]
Assets, Fair Value Disclosure		16,294
Fair Value, Inputs, Level 2 [Member] | Commodity Mutual Fund [Member]
Assets, Fair Value Disclosure		$ 222
Fair Value, Inputs, Level 3 [Member] | U S Treasury Mutual Fund [Member]
Assets, Fair Value Disclosure	$ 0