Note 10 - Employment Benefit and Retirement Plans - Obligations and Funded Status (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Director Retirement Plan [Member]
Benefit obligation at beginning of year	$ 285,053	$ 311,283
Service cost	0	0
Interest cost	12,000	12,000
Actuarial loss (gain)	30,847	(14,345)
Benefits paid	(22,500)	(23,885)
Assumed liability	0	0
Benefit obligation at end of year	305,400	285,053
Employer contributions	22,500	23,885
Benefits paid	(22,500)	(23,885)
Fair value of plan assets at year end	0	0
Funded status	(285,053)	(270,708)
Actuarial (gain) loss	(20,347)	(14,345)
Net amount recognized	(305,400)	(285,053)
Postretirement Health Coverage [Member]
Benefit obligation at beginning of year	303,220	293,449
Service cost		16,589
Interest cost		11,560
Actuarial loss (gain)		(14,989)
Benefits paid		(7,533)
Benefit obligation at end of year		303,220
Employer contributions	3,203	3,389
Benefits paid	(6,970)	(7,533)
Fair value of plan assets at year end	0	0
Funded status	(298,921)	(303,220)
Actuarial (gain) loss	(4,299)	4,299
Net amount recognized		(298,921)
Plan amendments
Retiree contributions		4,144
Termination of plan	(303,200)
Retiree contributions	3,767	4,299
Termination of Plan	$ 303,200