Note O - Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Balance	$ 152,762	$ 147,689	$ 153,094	$ 141,865
Change in accumulated other comprehensive income	(134)	172	201	1,550
Balance	154,215	151,372	154,215	151,372
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	304		(66)
Other comprehensive loss before reclassifications	(50)		332
Losses (gains) reclassified from accumulated other comprehensive income	(27)		(39)
Change in accumulated other comprehensive income	(77)		293
Balance	227		227
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(474)		(486)
Other comprehensive loss before reclassifications	0		0
Losses (gains) reclassified from accumulated other comprehensive income	6		18
Change in accumulated other comprehensive income	6		18
Balance	(468)		(468)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	(384)		(337)
Other comprehensive loss before reclassifications	(63)		(110)
Losses (gains) reclassified from accumulated other comprehensive income	0		0
Change in accumulated other comprehensive income	(63)		(110)
Balance	(447)		(447)
AOCI Attributable to Parent [Member]
Balance	(554)	(946)	(889)	(2,324)
Other comprehensive loss before reclassifications	(113)		274
Losses (gains) reclassified from accumulated other comprehensive income	(21)		(73)
Change in accumulated other comprehensive income	(134)	172	201	1,550
Balance	(688)	$ (774)	(688)	$ (774)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Balance			0
Other comprehensive loss before reclassifications			52
Losses (gains) reclassified from accumulated other comprehensive income			(52)
Change in accumulated other comprehensive income			0
Balance	$ 0		$ 0