Note 3 - Loans and Allowance for Loan Losses - Troubled Debt Restructurings (Details)	12 Months Ended
Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Number of loans	1	2
Pre-modification outstanding recorded balance	$ 119,459	$ 5,741,189
Post-modification outstanding recorded balance	$ 119,459	$ 5,741,189
Residential Portfolio Segment [Member] \| Real Estate Residential, One To Four Family Units [Member]
Number of loans	0	0
Pre-modification outstanding recorded balance	$ 0	$ 0
Post-modification outstanding recorded balance	$ 0	$ 0
Residential Portfolio Segment [Member] \| Real Estate Residential, Multi Family Units [Member]
Number of loans	0	0
Pre-modification outstanding recorded balance	$ 0	$ 0
Post-modification outstanding recorded balance	$ 0	$ 0
Real Estate, Construction [Member]
Number of loans	0	0
Pre-modification outstanding recorded balance	$ 0	$ 0
Post-modification outstanding recorded balance	$ 0	$ 0
Commercial Real Estate Portfolio Segment [Member]
Number of loans	0	1
Pre-modification outstanding recorded balance	$ 0	$ 5,575,358
Post-modification outstanding recorded balance	$ 0	$ 5,575,358
Commercial Portfolio Segment [Member]
Number of loans	0	1
Pre-modification outstanding recorded balance	$ 0	$ 165,831
Post-modification outstanding recorded balance	$ 0	$ 165,831
Consumer and Other Loans [Member]
Number of loans	1
Pre-modification outstanding recorded balance	$ 119,459
Post-modification outstanding recorded balance	$ 119,459

Number of financing receivables that have been modified by troubled debt restructurings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

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