Note O - Employee and Director Benefit Plans - Change in Plan Assets (Details) - Other Postretirement Benefits Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair value of plan assets	$ 0	$ 0	$ 0
Employer contribution	20	28	48
Benefits paid, net	(20)	(28)	(48)
Fair value of plan assets	$ 0	$ 0	$ 0