Fair Value (Fair Value of Assets on Nonrecurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Loans, fair value	$ 891	$ 897
Foreclosed asset, fair value	347	84
Fair Value, Measurements, Nonrecurring [Member]
Loans, fair value	891	897
Foreclosed asset, fair value	347	84
Fair Value, Measurements, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Loans, fair value	891	897
Foreclosed asset, fair value	$ 347	$ 84

Fair value portion of impaired loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

No definition available.

Name:	ffbw_ImpairedLoansReceivableFairValueDisclosure
Namespace Prefix:	ffbw_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant