Note 10 - Employment Benefit and Retirement Plans - Amounts Recognized in Statement of Financial Position (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Director Retirement Plan [Member]
Accumulated post-retirement benefit obligation	$ (305,400)	$ (270,708)
Plan assets at fair value	0	0
Funded status	(285,053)	(270,708)
Actuarial gain	(20,347)	(14,345)
(Accrued) cost included in other liabilities	(305,400)	(285,053)
Director Retirement Plan [Member] \| Active Participants [Member]
Accumulated post-retirement benefit obligation	(128,469)	(106,093)
Director Retirement Plan [Member] \| Retired Participants Including Beneficiaries [Member]
Accumulated post-retirement benefit obligation	(176,931)	(164,615)
Postretirement Health Coverage [Member]
Accumulated post-retirement benefit obligation		(298,921)
Plan assets at fair value	0	0
Funded status	(298,921)	(303,220)
Actuarial gain	(4,299)	4,299
(Accrued) cost included in other liabilities		(298,921)
Postretirement Health Coverage [Member] \| Retirees [Member]
Accumulated post-retirement benefit obligation		(59,636)
Postretirement Health Coverage [Member] \| Active Employees Fully Eligible [Member]
Accumulated post-retirement benefit obligation		0
Postretirement Health Coverage [Member] \| Active Employees Not Yet Eligible [Member]
Accumulated post-retirement benefit obligation		$ (239,285)

The funded status of the defined benefit plan before actuarial gain (loss) and plan termination.

No definition available.

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- Definition

Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

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- Definition

Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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- Definition

Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

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- Definition

Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans.

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Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent.

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