XML 41 R30.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Schedule of Mortgage-Backed Securities by Weighted Average Life (Details) - USD ($) $ in Thousands | Sep. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value |  | $ 1,575,983 | $ 1,685,998
Non-Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value |  | 11,952 | 18,025
Amortized Cost |  | $ 9,908 | $ 15,278
Weighted Average Coupon Rate, Percent |  | 4.38% | 3.58%
Less than three years [Member] | Non-Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 5,033 | $ 0
Amortized Cost | [1] | $ 4,259 | $ 0
Weighted Average Coupon Rate, Percent | [1] | 5.28% | 0.00%
Greater than three years and less than seven years [Member] | Non-Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 2,611 | $ 9,625
Amortized Cost | [1] | $ 2,465 | $ 9,062
Weighted Average Coupon Rate, Percent | [1] | 5.84% | 5.00%
Greater than seven years and less than eleven years [Member] | Non-Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 4,308 | $ 5,892
Amortized Cost | [1] | $ 3,184 | $ 3,697
Weighted Average Coupon Rate, Percent | [1] | 2.69% | 2.14%
Greater than eleven years [Member] | Non-Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 0 | $ 2,508
Amortized Cost | [1] | $ 0 | $ 2,519
Weighted Average Coupon Rate, Percent | [1] | 0.00% | 2.18%
Fixed Rate [Member] | Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value |  | $ 1,545,347 | $ 1,655,768
Amortized Cost |  | $ 1,592,424 | $ 1,669,060
Weighted Average Coupon Rate, Percent |  | 4.07% | 3.92%
Fixed Rate [Member] | Less than three years [Member] | Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 4,376 | $ 7,931
Amortized Cost | [1] | $ 4,451 | $ 7,935
Weighted Average Coupon Rate, Percent | [1] | 4.12% | 3.70%
Fixed Rate [Member] | Greater than three years and less than seven years [Member] | Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 312,760 | $ 419,295
Amortized Cost | [1] | $ 323,265 | $ 423,248
Weighted Average Coupon Rate, Percent | [1] | 4.00% | 3.93%
Fixed Rate [Member] | Greater than seven years and less than eleven years [Member] | Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 1,208,634 | $ 1,221,160
Amortized Cost | [1] | $ 1,244,869 | $ 1,230,479
Weighted Average Coupon Rate, Percent | [1] | 4.08% | 3.92%
Fixed Rate [Member] | Greater than eleven years [Member] | Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 19,577 | $ 7,382
Amortized Cost | [1] | $ 19,839 | $ 7,398
Weighted Average Coupon Rate, Percent | [1] | 3.99% | 3.68%
Interest-Only [Member] | Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value |  | $ 18,684 | $ 12,205
Amortized Cost |  | $ 17,601 | $ 13,197
Weighted Average Coupon Rate, Percent |  | 4.44% | 4.36%
Interest-Only [Member] | Less than three years [Member] | Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 1,132 | $ 3,357
Amortized Cost | [1] | $ 1,517 | $ 4,253
Weighted Average Coupon Rate, Percent | [1] | 4.51% | 4.15%
Interest-Only [Member] | Greater than three years and less than seven years [Member] | Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 17,552 | $ 8,848
Amortized Cost | [1] | $ 16,084 | $ 8,944
Weighted Average Coupon Rate, Percent | [1] | 4.43% | 4.51%
Interest-Only [Member] | Greater than seven years and less than eleven years [Member] | Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 0 | $ 0
Amortized Cost | [1] | $ 0 | $ 0
Weighted Average Coupon Rate, Percent | [1] | 0.00% | 0.00%
Interest-Only [Member] | Greater than eleven years [Member] | Agency RMBS [Member] |  |  |
Mortgage-Backed Securities [Line Items] |  |  |
Mortgage-backed securities, at fair value | [1] | $ 0 | $ 0
Amortized Cost | [1] | $ 0 | $ 0
Weighted Average Coupon Rate, Percent | [1] | 0.00% | 0.00%
[1] | Average lives of RMBS are generally shorter than stated contractual maturities.

X
- Definition [Line Items] for Mortgage-Backed Securities [Table] + References No definition available. + Details
Name: | earn_MortgageBackedSecuritiesLineItems
Namespace Prefix: | earn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted Average Coupon Rate, Percent + References No definition available. + Details
Name: | earn_WeightedAverageCouponRatePercent
Namespace Prefix: | earn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The fair value as of the balance sheet date of firm holdings in mortgages, mortgage backed securities (investment instruments that represent ownership of an undivided interest in a group of mortgages, where principal and interest from the individual mortgages are used to pay investors' principal and interest on the mortgage backed security) and asset-backed securities that are primarily paid from the cash flows of a discrete pool of receivables or other financial assets (such as credit-card receivables), either fixed or revolving, that by their terms convert into cash within a finite time period. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 940 -SubTopic 320 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=35711157&loc=d3e42546-110969 + Details
Name: | us-gaap_FinancialInstrumentsOwnedMortgagesMortgageBackedAndAssetBackedSecuritiesAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Cost of the investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 210 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=99383244&loc=d3e12121-115841 + Details
Name: | us-gaap_InvestmentOwnedAtCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | earn_WeightedaveragelifebyrangeAxis=earn_LessthanthreeyearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | earn_WeightedaveragelifebyrangeAxis=earn_GreaterthanthreeyearsandlessthansevenyearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | earn_WeightedaveragelifebyrangeAxis=earn_GreaterthansevenyearsandlessthanelevenyearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | earn_WeightedaveragelifebyrangeAxis=earn_GreaterthanelevenyearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_FixedIncomeSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_InterestOnlyStripMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |