XML 52 R41.htm IDEA: XBRL DOCUMENT v3.8.0.1

Schedule of Derivative Activity (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Interest Rate Swap [Member]
Derivative [Line Items]
Financial derivative average monthly notional	$ 630,497	$ 549,907
TBA securities [Member]
Derivative [Line Items]
Financial derivative average monthly notional	707,333	796,813
Futures [Member]
Derivative [Line Items]
Financial derivative average monthly notional	172,575	30,092
Swaption [Member]
Derivative [Line Items]
Financial derivative average monthly notional	$ 10,000	$ 4,615

X

- Definition

Average notional for the period using absolute value of month end notional amounts.

+ References

No definition available.

+ Details

Name:	earn_Financialderivativeaveragemonthlynotional
Namespace Prefix:	earn_
Data Type:	xbrli:monetaryItemType
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_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=earn_TBAsecuritiesMember
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:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_SwaptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: