Note O - Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Balance	$ 156,238	$ 153,094
Change in accumulated other comprehensive loss	(249)	(235)
Balance	158,906	149,979
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	360
Other comprehensive income (loss) before reclassifications	(304)
Losses (gains) reclassified from accumulated other comprehensive income (loss)	8
Change in accumulated other comprehensive loss	(296)
Balance	64
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Balance	0
Other comprehensive income (loss) before reclassifications	10
Losses (gains) reclassified from accumulated other comprehensive income (loss)	(4)
Change in accumulated other comprehensive loss	6
Balance	6
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(491)
Other comprehensive income (loss) before reclassifications	0
Losses (gains) reclassified from accumulated other comprehensive income (loss)	6
Change in accumulated other comprehensive loss	6
Balance	(485)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	(506)
Other comprehensive income (loss) before reclassifications	35
Losses (gains) reclassified from accumulated other comprehensive income (loss)	0
Change in accumulated other comprehensive loss	35
Balance	(471)
AOCI Attributable to Parent [Member]
Balance	(637)	(889)
Other comprehensive income (loss) before reclassifications	(259)
Losses (gains) reclassified from accumulated other comprehensive income (loss)	10
Change in accumulated other comprehensive loss	(249)	(235)
Balance	$ (886)	$ (1,124)