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v3.23.3

Summary of Significant Accounting Policies - Contingencies (Details) | 9 Months Ended
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Sep. 30, 2023
Accounting Policies [Abstract] |
Commitment, Period | 10 years

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- Definition Commitment, Period + References No definition available. + Details
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Namespace Prefix: | mfa_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
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Namespace Prefix: | us-gaap_
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Balance Type: | na
Period Type: | duration