XML 50 R39.htm IDEA: XBRL DOCUMENT v3.25.3

Summary of Significant Accounting Policies - Residential Whole Loans (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
LTV ratio (as a percent)	80.00%
Residential whole loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
LTV ratio (as a percent)	64.00%	64.00%
Residential whole loans | Business purpose loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
LTV ratio (as a percent)	67.00%	67.00%
Residential whole loans | Business purpose loans | Multifamily Properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold balance (below)	$ 10

X

- Definition

Financing Receivable, Threshold Balance

+ References

No definition available.

+ Details

Name:	mfa_FinancingReceivableThresholdBalance
Namespace Prefix:	mfa_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The LTV of which the Company has assessed its residential whole loans at carrying value will have a higher likelihood of default than newly originated mortgage loans

+ References

No definition available.

+ Details

Name:	mfa_FinancingReceivableWeightedAverageLoanToValueRatio
Namespace Prefix:	mfa_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- 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/2009/role/commonPracticeRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 40
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481628/310-20-40-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

+ Details

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

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=mfa_ResidentialWholeLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mfa_BusinessPurposeLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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