Note P - Fair Value Measurements and Disclosures - Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Available for sale securities	$ 196,311	$ 222,110
Fair Value, Inputs, Level 1 [Member]
Available for sale securities
Fair Value, Recurring [Member]
Available for sale securities	196,311	222,110
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available for sale securities	196,311	222,110
US Treasury Securities [Member]
Available for sale securities	55,653	83,423
US Treasury Securities [Member] | Fair Value, Recurring [Member]
Available for sale securities	55,653	83,423
US Treasury Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available for sale securities	55,653	83,423
US Government Agencies Debt Securities [Member]
Available for sale securities	12,570	17,247
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member]
Available for sale securities	12,570	17,247
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available for sale securities	12,570	17,247
Collateralized Mortgage Backed Securities [Member]
Available for sale securities	106,153	110,344
Collateralized Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
Available for sale securities	106,153	110,344
Collateralized Mortgage Backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available for sale securities	106,153	110,344
Collateralized Mortgage Obligations [Member]
Available for sale securities	15,488
Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member]
Available for sale securities	15,488
Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available for sale securities	15,488
US States and Political Subdivisions Debt Securities [Member]
Available for sale securities	6,447	11,096
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member]
Available for sale securities	6,447	11,096
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available for sale securities	$ 6,447	$ 11,096