Note B - Securities - Available for Sale and Held to Maturity Securities with Gross Unrealized Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Less Than Twelve Months, Fair Value	$ 255,560	$ 268,224
Less Than Twelve Months, Gross Unrealized Losses	13,104	4,788
Over Twelve Months, Fair Value	256,453	7,470
Over Twelve Months, Gross Unrealized Losses	49,911	368
Total, Fair Value	512,013	275,694
Total, Gross Unrealized Losses	63,015	5,156
US Treasury Securities [Member]
Less Than Twelve Months, Fair Value	132,113	73,154
Less Than Twelve Months, Gross Unrealized Losses	2,158	735
Over Twelve Months, Fair Value	64,533
Over Twelve Months, Gross Unrealized Losses	9,544
Total, Fair Value	196,646	73,154
Total, Gross Unrealized Losses	11,702	735
Collateralized Mortgage-Backed Securities [Member]
Less Than Twelve Months, Fair Value	25,234	26,288
Less Than Twelve Months, Gross Unrealized Losses	1,755	441
Over Twelve Months, Fair Value	21,850
Over Twelve Months, Gross Unrealized Losses	3,122
Total, Fair Value	47,084	26,288
Total, Gross Unrealized Losses	4,877	441
Collateralized Mortgage Obligations [Member]
Less Than Twelve Months, Fair Value	48,188	66,369
Less Than Twelve Months, Gross Unrealized Losses	1,610	1,035
Over Twelve Months, Fair Value	59,189
Over Twelve Months, Gross Unrealized Losses	6,449
Total, Fair Value	107,377	66,369
Total, Gross Unrealized Losses	8,059	1,035
US States and Political Subdivisions Debt Securities [Member]
Less Than Twelve Months, Fair Value	50,025	102,413
Less Than Twelve Months, Gross Unrealized Losses	7,581	2,577
Over Twelve Months, Fair Value	110,881	7,470
Over Twelve Months, Gross Unrealized Losses	30,796	368
Total, Fair Value	160,906	109,883
Total, Gross Unrealized Losses	$ 38,377	$ 2,945