Note 3 - Loans Held for Investment, Net - Impaired Loans (Details) - USD ($)	9 Months Ended	12 Months Ended
Sep. 30, 2018	Dec. 31, 2017
Impaired loans, with no related allowance recorded, recorded investment	$ 4,794,477	$ 5,436,972
Impaired loans, with no related allowance recorded, principal net of charge-offs	4,794,477	5,436,972
Impaired loans, with no related allowance recorded, average recorded investment	4,864,787	5,503,793
Impaired loans, with an allowance recorded, recorded investment		0
Impaired loans, related allowance	215,000	0
Impaired loans, with an allowance recorded, average recorded investment		0
Impaired loans, fair value disclosure	5,344,477	5,436,972
Impaired loans, principal net of charge-offs	5,344,477	5,436,972
Impaired loans, average recorded investment	5,414,787	5,503,793
Impaired loans, with an allowance recorded, recorded investment		0
Commercial Real Estate Portfolio Segment [Member]
Impaired loans, with no related allowance recorded, recorded investment	3,021,208	3,483,078
Impaired loans, with no related allowance recorded, principal net of charge-offs	3,021,208	3,483,078
Impaired loans, with no related allowance recorded, average recorded investment	3,054,043	3,521,421
Impaired loans, with an allowance recorded, recorded investment	550,000
Impaired loans, with an allowance recorded, principal net of charge-offs	550,000
Impaired loans, related allowance	215,000	0
Impaired loans, with an allowance recorded, average recorded investment	550,000
Impaired loans, fair value disclosure	3,571,208	3,483,078
Impaired loans, principal net of charge-offs	3,571,208	3,483,078
Impaired loans, average recorded investment	3,604,043	3,521,421
Impaired loans, with an allowance recorded, recorded investment	550,000
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Impaired loans, with no related allowance recorded, recorded investment	663,580	679,184
Impaired loans, with no related allowance recorded, principal net of charge-offs	663,580	679,184
Impaired loans, with no related allowance recorded, average recorded investment	680,907	684,632
Impaired loans, related allowance	0	0
Impaired loans, fair value disclosure	663,580	679,184
Impaired loans, principal net of charge-offs	663,580	679,184
Impaired loans, average recorded investment	680,907	684,632
Commercial and Industrial Portfolio Segment [Member]
Impaired loans, with no related allowance recorded, recorded investment	1,109,689	1,274,710
Impaired loans, with no related allowance recorded, principal net of charge-offs	1,109,689	1,274,710
Impaired loans, with no related allowance recorded, average recorded investment	1,129,837	1,297,740
Impaired loans, related allowance	0	0
Impaired loans, fair value disclosure	1,109,689	1,274,710
Impaired loans, principal net of charge-offs	1,109,689	1,274,710
Impaired loans, average recorded investment	1,129,837	1,297,740
Consumer and Other Portfolio Segment [Member]
Impaired loans, with no related allowance recorded, recorded investment	0	0
Impaired loans, with no related allowance recorded, principal net of charge-offs	0	0
Impaired loans, with no related allowance recorded, average recorded investment	0	0
Impaired loans, related allowance	0	0
Impaired loans, fair value disclosure	0	0
Impaired loans, principal net of charge-offs	0	0
Impaired loans, average recorded investment	$ 0	$ 0

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
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