Note B - Securities - Available for Sale and Held to Maturity Securities with Gross Unrealized Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Less Than Twelve Months, Fair Value	$ 27,561	$ 255,560
Less Than Twelve Months, Gross Unrealized Losses	42	13,104
Over Twelve Months, Fair Value	295,559	256,453
Over Twelve Months, Gross Unrealized Losses	39,762	49,911
Total, Fair Value	323,120	512,013
Total, Gross Unrealized Losses	39,804	63,015
US Treasury Securities [Member]
Less Than Twelve Months, Fair Value	24,750	132,113
Less Than Twelve Months, Gross Unrealized Losses	22	2,158
Over Twelve Months, Fair Value	85,660	64,533
Over Twelve Months, Gross Unrealized Losses	8,520	9,544
Total, Fair Value	110,410	196,646
Total, Gross Unrealized Losses	8,542	11,702
Collateralized Mortgage-Backed Securities [Member]
Less Than Twelve Months, Fair Value	2,811	25,234
Less Than Twelve Months, Gross Unrealized Losses	20	1,755
Over Twelve Months, Fair Value	38,521	21,850
Over Twelve Months, Gross Unrealized Losses	4,583	3,122
Total, Fair Value	41,332	47,084
Total, Gross Unrealized Losses	4,603	4,877
Collateralized Mortgage Obligations [Member]
Less Than Twelve Months, Fair Value	0	48,188
Less Than Twelve Months, Gross Unrealized Losses	0	1,610
Over Twelve Months, Fair Value	90,290	59,189
Over Twelve Months, Gross Unrealized Losses	6,327	6,449
Total, Fair Value	90,290	107,377
Total, Gross Unrealized Losses	6,327	8,059
US States and Political Subdivisions Debt Securities [Member]
Less Than Twelve Months, Fair Value	0	50,025
Less Than Twelve Months, Gross Unrealized Losses	0	7,581
Over Twelve Months, Fair Value	81,088	110,881
Over Twelve Months, Gross Unrealized Losses	20,332	30,796
Total, Fair Value	81,088	160,906
Total, Gross Unrealized Losses	$ 20,332	$ 38,377