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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Balance	$ 156,129	$ 152,762	$ 156,238	$ 153,094
Change in accumulated other comprehensive income (loss)	(101)	(134)	(434)	201
Balance	159,434	154,215	159,434	154,215
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	10		358
Other comprehensive income (loss) before reclassifications	(100)		(456)
Losses (gains) reclassified from accumulated other comprehensive income	(30)		(22)
Change in accumulated other comprehensive income (loss)	(130)		(478)
Balance	(120)		(120)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Balance	0		0
Other comprehensive income (loss) before reclassifications	0		31
Losses (gains) reclassified from accumulated other comprehensive income	0		(31)
Change in accumulated other comprehensive income (loss)	0		0
Balance	0		0
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(479)		(491)
Other comprehensive income (loss) before reclassifications	0		0
Losses (gains) reclassified from accumulated other comprehensive income	6		18
Change in accumulated other comprehensive income (loss)	6		18
Balance	(473)		(473)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	(501)		(504)
Other comprehensive income (loss) before reclassifications	23		26
Losses (gains) reclassified from accumulated other comprehensive income	0		0
Change in accumulated other comprehensive income (loss)	23		26
Balance	(478)		(478)
AOCI Attributable to Parent [Member]
Balance	(970)	(554)	(637)	(889)
Other comprehensive income (loss) before reclassifications	(77)		(399)
Losses (gains) reclassified from accumulated other comprehensive income	(24)		(35)
Change in accumulated other comprehensive income (loss)	(101)	(134)	(434)	201
Balance	$ (1,071)	$ (688)	$ (1,071)	$ (688)