Mortgage Loans On Real Estate, Amortization (Discount) Accretion, Net

No definition available.

Name:	mfa_MortgageLoansOnRealEstateAmortizationDiscountAccretionNet
Namespace Prefix:	mfa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Mortgage Loans On Real Estate, Provision For Loan Loss

+ References

No definition available.

+ Details

Name:	mfa_MortgageLoansOnRealEstateProvisionForLoanLoss
Namespace Prefix:	mfa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Mortgage Loans On Real Estate, Transfer To REO

+ References

No definition available.

+ Details

Name:	mfa_MortgageLoansOnRealEstateTransferToREO
Namespace Prefix:	mfa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Additions

+ References

No definition available.

+ Details

Name:	mfa_SECSchedule1229RealEstateCompaniesInvestmentInMortgageLoansOnRealEstateAdditionsAbstract
Namespace Prefix:	mfa_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Change In Fair Value

+ References

No definition available.

+ Details

Name:	mfa_SECSchedule1229RealEstateCompaniesInvestmentInMortgageLoansOnRealEstateChangeInFairValue
Namespace Prefix:	mfa_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Deduction

+ References

No definition available.

+ Details

Name:	mfa_SECSchedule1229RealEstateCompaniesInvestmentInMortgageLoansOnRealEstateDeductionAbstract
Namespace Prefix:	mfa_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Impairment

+ References

No definition available.

+ Details

Name:	mfa_SECSchedule1229RealEstateCompaniesInvestmentInMortgageLoansOnRealEstateImpairment
Namespace Prefix:	mfa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of decrease in investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate, from collection of principal.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Footnote 6
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Footnote 6))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

Name:	srt_MortgageLoansOnRealEstateCollectionsOfPrincipal
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of principal due on delinquent mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate, acquired from controlled and other affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Footnote 10(b)
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Footnote 10(b)))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

Name:	srt_MortgageLoansOnRealEstateDelinquentPrincipalOrInterestAcquiredFromAffiliates
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of contractual principal due at origination of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Paragraph Column F
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column F))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

Name:	srt_MortgageLoansOnRealEstateFaceAmountOfMortgages
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of federal income tax basis of investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Footnote 8
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Footnote 8))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

Name:	srt_MortgageLoansOnRealEstateFederalIncomeTaxBasis1
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Interest rate of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Paragraph Column B
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column B))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

Name:	srt_MortgageLoansOnRealEstateInterestRate
Namespace Prefix:	srt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

Name:	srt_MortgageLoansOnRealEstateLineItems
Namespace Prefix:	srt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of mortgage loans within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Footnote 3
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Footnote 3))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

Name:	srt_MortgageLoansOnRealEstateNumberOfLoans
Namespace Prefix:	srt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Paragraph Column H
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column H))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

Name:	srt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(4))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (1)
-Publisher SEC

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (3)
-Publisher SEC

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (c)
-Publisher SEC

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

+ Details

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

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Publisher FASB
-URI https://asc.fasb.org//310-10/tableOfContent

+ Details

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

- Definition

Amount of investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column G))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

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

- Definition

Amount of decrease in investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate, from sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Footnote 6))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

Name:	us-gaap_MortgageLoansOnRealEstateCostOfMortgagesSold
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate, from new investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Footnote 6))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

Name:	us-gaap_MortgageLoansOnRealEstateNewMortgageLoans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

Name:	us-gaap_MovementInMortgageLoansOnRealEstateRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=mfa_ResidentialWholeLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mfa_MortgageLoansOnRealEstateLoanBalanceAxis=mfa_OriginalLoanBalanceRange1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mfa_MortgageLoansOnRealEstateLoanBalanceAxis=mfa_OriginalLoanBalanceRange2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mfa_MortgageLoansOnRealEstateLoanBalanceAxis=mfa_OriginalLoanBalanceRange3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mfa_MortgageLoansOnRealEstateLoanBalanceAxis=mfa_OriginalLoanBalanceRange4Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Schedule IV - Mortgage Loans on Real Estate (Details)	12 Months Ended
Schedule IV - Mortgage Loans on Real Estate (Details)	Dec. 31, 2023 USD ($) loan	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Allowance for credit loss	$ 20,451,000	$ 28,557,000	$ 31,035,000	$ 33,062,000	$ 35,314,000	$ 37,192,000	$ 36,927,000	$ 35,457,000	$ 39,447,000
Residential Whole Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number \| loan	25,401
Balance Sheet Reported Amount	$ 8,958,089,000
Principal Amount of Loans Subject to Delinquent Principal or Interest	508,513,000
Allowance for credit loss	20,500,000
Loans, fair value	103,700,000
Tax basis of loans	4,200,000,000
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Beginning Balance	7,518,739,000
Additions during period:
Purchases	2,986,617,000
Premium amortization/discount accretion, net	13,819,000
Reversal of provision for loan loss	14,863,000
Changes in fair value recorded in gain/(loss) on loans recorded at fair value	114,065,000
Deductions during period:
Repayments	(1,437,711,000)
Loan sales and repurchases	(94,624,000)
Impairment on carrying value loans	(1,240,000)
Transfer to REO	(73,236,000)
Ending Balance	$ 9,041,292,000
Residential Whole Loans \| Original loan balance $0 - $149,999
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number \| loan	7,596
Balance Sheet Reported Amount	$ 663,042,000
Principal Amount of Loans Subject to Delinquent Principal or Interest	$ 45,934,000
Residential Whole Loans \| Original loan balance $0 - $149,999 \| Minimum
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rate	0.00%
Original loan balance	$ 0
Residential Whole Loans \| Original loan balance $0 - $149,999 \| Maximum
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rate	16.00%
Original loan balance	$ 149,999
Residential Whole Loans \| Original loan balance $150,000 - $299,999
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number \| loan	8,130
Balance Sheet Reported Amount	$ 1,474,946,000
Principal Amount of Loans Subject to Delinquent Principal or Interest	$ 105,669,000
Residential Whole Loans \| Original loan balance $150,000 - $299,999 \| Minimum
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rate	0.00%
Original loan balance	$ 150,000
Residential Whole Loans \| Original loan balance $150,000 - $299,999 \| Maximum
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rate	14.65%
Original loan balance	$ 299,999
Residential Whole Loans \| Original loan balance $300,000 - $449,999
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number \| loan	3,840
Balance Sheet Reported Amount	$ 1,151,268,000
Principal Amount of Loans Subject to Delinquent Principal or Interest	$ 90,826,000
Residential Whole Loans \| Original loan balance $300,000 - $449,999 \| Minimum
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rate	0.00%
Original loan balance	$ 300,000
Residential Whole Loans \| Original loan balance $300,000 - $449,999 \| Maximum
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rate	13.88%
Original loan balance	$ 449,999
Residential Whole Loans \| Original loan balance greater than $449,999
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number \| loan	5,835
Balance Sheet Reported Amount	$ 5,668,833,000
Principal Amount of Loans Subject to Delinquent Principal or Interest	266,084,000
Original loan balance	$ 449,999
Residential Whole Loans \| Original loan balance greater than $449,999 \| Minimum
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rate	0.70%
Residential Whole Loans \| Original loan balance greater than $449,999 \| Maximum
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rate	15.00%