Note 1 - Nature of Operations and Summary of Significant Accounting and Reporting Policies (Details Textual)		1 Months Ended	12 Months Ended
	Oct. 11, 2016 USD ($) $ / shares shares	Oct. 31, 2016 $ / shares shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares
Stock Issued During Period, Shares, New Issues | shares	1,879,484
Stock Issued During Period, Shares, Employee Stock Purchase Plans | shares	150,358	150,358
Shares Issued, Price Per Share | $ / shares	$ 10	$ 10
Stock Issued During Period, Value, New Issues	$ 18,800,000
Payments of Stock Issuance Costs	$ 1,300,000
Stockholders' Equity Note, Stock Split, Conversion Ratio	2.0473
Conversion of Stock, Shares Issued | shares	1,558,706
Common Stock, Shares, Outstanding, Ending Balance | shares	3,438,190		3,374,565	3,490,672
Advertising Expense			$ 527,142	$ 453,976
Unrecognized Tax Benefits, Ending Balance			$ 0	0
Core Deposits [Member]
Finite-Lived Intangible Asset, Useful Life			9 years
One-to-four Family Residential Real Estate Portfolio Segment [Member]
Loans Receivable Held-for-sale, Amount			$ 26,900,000	$ 15,400,000
Minimum [Member] | Equipment [Member]
Property, Plant and Equipment, Useful Life			3 years
Minimum [Member] | Leasehold Improvements and Buildings [Member]
Property, Plant and Equipment, Useful Life			15 years
Minimum [Member] | One-to-four Family Residential Real Estate Portfolio Segment [Member]
Loans Receivable Selling Period			7 days
Maximum [Member] | Equipment [Member]
Property, Plant and Equipment, Useful Life			7 years
Maximum [Member] | Leasehold Improvements and Buildings [Member]
Property, Plant and Equipment, Useful Life			40 years
Maximum [Member] | One-to-four Family Residential Real Estate Portfolio Segment [Member]
Loans Receivable Selling Period			14 days