Note 7 - Fair Values of Financial Instruments - Significant Unobservable Inputs (Details)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Impaired loans, fair value disclosure	$ 3,605,635	$ 3,643,608
Commercial Real Estate Portfolio Segment [Member]
Impaired loans, fair value disclosure	2,988,885	2,993,923
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Impaired loans, fair value disclosure	616,750	649,685
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Impaired loans, fair value disclosure	3,605,635	3,643,608
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Valuation, Market Approach [Member] \| Commercial Real Estate Portfolio Segment [Member]
Impaired loans, fair value disclosure	$ 2,988,885	$ 2,993,923
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Valuation, Market Approach [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Minimum [Member] \| Measurement Input, Discount Rate [Member]
Impaired loans, Unobservable input valuation	0.17	0.17
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Valuation, Market Approach [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Maximum [Member] \| Measurement Input, Discount Rate [Member]
Impaired loans, Unobservable input valuation	0.18	0.18
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Valuation, Market Approach [Member] \| One-to-four Family Residential Real Estate Portfolio Segment [Member]
Impaired loans, fair value disclosure	$ 616,750	$ 649,685
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Valuation, Market Approach [Member] \| One-to-four Family Residential Real Estate Portfolio Segment [Member] \| Minimum [Member] \| Measurement Input, Discount Rate [Member]
Impaired loans, Unobservable input valuation	0.17	0.17
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Valuation, Market Approach [Member] \| One-to-four Family Residential Real Estate Portfolio Segment [Member] \| Maximum [Member] \| Measurement Input, Discount Rate [Member]
Impaired loans, Unobservable input valuation	0.18	0.18
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Internal Estimate [member]
Derivative IRLC's, fair value disclosure	$ 360,830	$ 380,866
Derivative IRLC's, Unobservable input valuation		0.77
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Internal Estimate [member] \| Measurement Input, Pull-through Rate [Member]
Derivative IRLC's, Unobservable input valuation	0.73
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Internal Estimate [member] \| Maximum [Member] \| Measurement Input, Pull-through Rate [Member]
Derivative IRLC's, Unobservable input valuation

Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Valuation, Market Approach [Member] | Commercial Real Estate Portfolio Segment [Member]

Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Valuation, Market Approach [Member] | One-to-four Family Residential Real Estate Portfolio Segment [Member]

Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Internal Estimate [member]

Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Internal Estimate [member] | Measurement Input, Pull-through Rate [Member]

Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Internal Estimate [member] | Maximum [Member] | Measurement Input, Pull-through Rate [Member]