Note 6 - Deposits - Composition of Deposits (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Non-interest bearing checking	$ 18,438	$ 22,271
Interest bearing checking	4,794	4,017
Money market	50,379	54,472
Statement savings accounts	13,981	14,030
Health savings accounts	11,512	11,335
Certificates of deposit	67,230	76,788
Total	$ 166,334	$ 182,913

Amount of interest-bearing domestic health deposit liabilities.

No definition available.

Name:	ffbw_InterestBearingDomesticDepositHealth
Namespace Prefix:	ffbw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Total amount of interest-bearing domestic deposit liabilities, which may include brokered, retail, demand, checking, notice of withdrawal, money market and other interest-bearing deposits.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.12)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_InterestBearingDepositLiabilitiesDomestic
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest-bearing domestic certificate of deposit liabilities.

+ References

+ Details

Name:	us-gaap_InterestBearingDomesticDepositCertificatesOfDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest-bearing domestic checking deposit liabilities.

+ References

+ Details

Name:	us-gaap_InterestBearingDomesticDepositChecking
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest-bearing domestic money market demand account deposit liabilities.

+ References

+ Details

Name:	us-gaap_InterestBearingDomesticDepositMoneyMarket
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest-bearing domestic savings deposit liabilities. Saving deposits bear interest and have no stated maturity.

+ References

+ Details

Name:	us-gaap_InterestBearingDomesticDepositSavings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of noninterest-bearing domestic checking deposit liabilities.

+ References

+ Details

Name:	us-gaap_NoninterestBearingDomesticDepositChecking
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant