Note A - Summary of Significant Accounting Policies - Components of Accumulated OCI, Net of Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Balance	$ 364,536	$ 413,812	$ 407,118
Period charge	7,039	(62,454)	(5,883)
Balance	380,146	364,536	413,812
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member]
Balance	(56,055)
Period charge	6,246
Balance	(49,809)	(56,055)
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Balance	(8,712)
Period charge	793
Balance	(7,919)	(8,712)
AOCI Attributable to Parent [Member]
Balance	(64,767)	(2,313)	3,570
Period charge	7,039	(62,454)	(5,883)
Balance	$ (57,728)	$ (64,767)	$ (2,313)