Note 2 - Nature of Business and Summary of Significant Accounting Policies (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		6 Months Ended
Oct. 10, 2017	Jun. 30, 2018	Jun. 30, 2017
Stock Issued During Period, Shares, New Issues	2,950,625
Sale of Stock, Price Per Share	$ 10
Payments of Stock Issuance Costs	$ 1,394
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total		$ 0	$ 0
FFBW Community Foundation [Member]
Stock Issued During Period, Shares, New Issues	25,000
Percentage of Common Stock Outstanding to Bank Eligible Members	45.00%
Percentage of Common Stock Subscribe to Adopt Employee Stock Ownership Plan	3.92%
FFBW, MHC [Member]
Percentage of Common Stock Outstanding Upon Completion of Reorganization and Stock Issuance	55.00%

Represents percentage of common stock outstanding to bank eligible members.

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Percentage of common stock to be outstanding upon completion of the reorganization and stock issuance.

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Percentage of common stock subscribe to adopt employee stock ownership plan.

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- Definition

The cash outflow for cost incurred directly with the issuance of an equity security.

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Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

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Number of new stock issued during the period.

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Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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