DERIVATIVE FINANCIAL INSTRUMENTS - TBA positions (Details) - 30 Year [Member] $ in Thousands	Dec. 31, 2020 USD ($)
Long [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	$ 137,000
Cost Basis	136,635
Market Value Of TBA Contract	139,408
Net Estimated Fair Value	2,773
2.0% [Member] \| Long [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	465,000
Cost Basis	479,531
Market Value Of TBA Contract	483,090
Net Estimated Fair Value	3,559
3.0% [Member] \| Short [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	328,000
Cost Basis	342,896
Market Value Of TBA Contract	343,682
Net Estimated Fair Value	$ (786)

This item represents the cost of TBA contracts.

No definition available.

Name:	orc_CostBasis
Namespace Prefix:	orc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the current market value of TBA contracts.

+ References

No definition available.

+ Details

Name:	orc_MarketValueOfTbaContract
Namespace Prefix:	orc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Nominal or face amount used to calculate payments on the derivative asset.

+ References

Reference 1: 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=121590274&loc=SL5579245-113959

Reference 2: 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=121590274&loc=SL5580258-113959

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeAssetNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

+ Details

Name:	us-gaap_DerivativeFairValueOfDerivativeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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

- Details

Name:	orc_TbaByMaturityAxisAxis=orc_ThirtyYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	orc_TbaByCouponAxis=orc_TwoPercentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	orc_TbaByCouponAxis=orc_ThreePercentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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