XML 53 R42.htm IDEA: XBRL DOCUMENT
v3.21.2

Summary of Significant Accounting Policies (Equity Based Compensation) (Details) - RSUs | 6 Months Ended
--- | ---
Jun. 30, 2021
Share based compensation |
Vesting period of restricted share units (RSUs) | 3 years
Period for measuring market condition of award | 3 years

X
- Definition Represents the period over which changes in the entity's closing stock price and dividends declared on the entity's common stock are measured to determine stockholder returns that represent a market condition upon which an employee's right to exercise an award is contingent. + References No definition available. + Details
Name: | mfa_ShareBasedCompensationArrangementByShareBasedPaymentAwardMarketConditionPeriod
Namespace Prefix: | mfa_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
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 No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |