XML 81 R105.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Fair Value of Financial Instruments (Assets Measured at Fair Value on a Nonrecurring Basis) (Details) - USD ($) $ in Millions | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Fair Value Disclosures [Abstract] |  |
Other real estate, fair value | $ 257.7 | $ 215.0

X
- Definition Other Real Estate, Fair Value + References No definition available. + Details
Name: | mfa_OtherRealEstateFairValue
Namespace Prefix: | mfa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration