XML 110 R97.htm IDEA: XBRL DOCUMENT v3.21.1

Fair Value of Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Other real estate, fair value	$ 20.1	$ 50.7

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