Note M - Subsequent Events (Details Textual) - USD ($) $ in Millions	Jan. 14, 2022	Mar. 12, 2021	Sep. 19, 2020	Jan. 31, 2022	Dec. 31, 2021
Stock Repurchase Program, Additional Authorized Amount		$ 3	$ 2
Stock Repurchase Program, Authorized Amount		$ 15	$ 12
Wells Fargo Bank, N.A. [Member]
Maximum Dividends Issued Upon Repurchasing Stock					$ 5
Subsequent Event [Member]
Stock Repurchase Program, Additional Authorized Amount	$ 3
Stock Repurchase Program, Authorized Amount	$ 18
Subsequent Event [Member] | Wells Fargo Bank, N.A. [Member]
Maximum Dividends Issued Upon Repurchasing Stock				$ 7