Sales of available-for-sale securities during the period.

No definition available.

Name:	afbi_SalesOfAvailableForSaleSecuritiesDuringPeriod
Namespace Prefix:	afbi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Available for sale and held to maturity securities.

+ References

No definition available.

+ Details

Name:	afbi_ScheduleOfAvailableForSaleAndHeldToMaturitySecuritiesLineItems
Namespace Prefix:	afbi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922888-210455

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_CollateralAxis=us-gaap_CollateralPledgedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_NontaxableMunicipalBondsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Investment Securities - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) Security	Mar. 31, 2021 Security	Dec. 31, 2021 USD ($)
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Number of available-for-sale securities in unrealized loss position less than 12 months	57
Number of available-for-sale securities in unrealized loss position 12 months or greater	4
Sales of available-for-sale securities	0	0
Debt Securities, Available-for-sale \| $	$ 45,911		$ 48,557
Collateral Pledged
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Debt Securities, Available-for-sale \| $	$ 2,500		2,800
Government Agency Securities
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Number of available-for-sale securities in unrealized loss position less than 12 months	4
U.S. Treasury Strip Bonds
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Number of available-for-sale securities in unrealized loss position less than 12 months	5
Debt Securities, Available-for-sale \| $	$ 4,677		5,050
Government Agency Mortgage-Backed Securities
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Number of available-for-sale securities in unrealized loss position less than 12 months	36
Debt Securities, Available-for-sale \| $	$ 19,015		21,339
Municipal Securities - Tax Exempt
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Number of available-for-sale securities in unrealized loss position less than 12 months	3
Debt Securities, Available-for-sale \| $	$ 488		536
Corporate Securities
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Number of available-for-sale securities in unrealized loss position less than 12 months	13
Debt Securities, Available-for-sale \| $	$ 9,525		$ 9,300