v3.20.1

Financial Derivatives (Futures) (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2020 | Dec. 31, 2019
Derivative [Line Items] |  |
Fair Value | $ (16,020) | $ (10,833)
Long | U.S. Treasury futures |  |
Derivative [Line Items] |  |
Notional Amount | 1,900 | 0
Fair Value | $ 37 | $ 0
Remaining Years to Maturity | 2 months 20 days | 0 days
Short | U.S. Treasury futures |  |
Derivative [Line Items] |  |
Notional Amount | $ (7,000) | $ (16,000)
Fair Value | $ (43) | $ 148
Remaining Years to Maturity | 2 months 16 days | 2 months 23 days
Short | Eurodollar futures |  |
Derivative [Line Items] |  |
Notional Amount | $ (172,100) | $ (14,000)
Fair Value | $ (6,006) | $ (45)
Remaining Years to Maturity | 2 months 29 days | 4 months 2 days
Short | Futures |  |
Derivative [Line Items] |  |
Notional Amount | $ (177,200) | $ (30,000)
Fair Value | $ (6,012) | $ 103
Remaining Years to Maturity | 2 months 29 days | 3 months 11 days

X
- Definition Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958 + Details
Name: | us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Period remaining until the derivative contract matures, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_DerivativeRemainingMaturity1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_PositionAxis=us-gaap_LongMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=efc_U.S.TreasuryFuturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PositionAxis=us-gaap_ShortMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_EurodollarFutureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_FutureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |