Mortgage-Backed Securities - By Maturity (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Mortgage Backed Securities [Abstract]
Less than one year	$ 0	$ 0
Greater than one year and less than five years	0	0
Greater than five years and less than ten years	967,000	1,521,000
Greater than or equal to ten years	1,548,204,000	349,702,000
Total mortgage-backed securities	$ 1,549,171,000	$ 351,223,000

Name:	orc_MortgageBackedSecuritiesAbstract
Namespace Prefix:	orc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Presentation of marketable securities with stated contractual maturities of five years through ten years.

+ References

No definition available.

+ Details

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

- Definition

Presentation of marketable securities with stated contractual maturities of one year through five years.

+ References

No definition available.

+ Details

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

- Definition

Presentation of marketable securities with stated contractual maturities greater than ten years.

+ References

No definition available.

+ Details

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

- Definition

Presentation of marketable securities with stated contractual maturities less than one year.

+ References

No definition available.

+ Details

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

- Definition

Fair value of securitized, pay-through debt securities collateralized by real estate mortgage loans classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Mortgage-Backed Securities

-URI http://asc.fasb.org/extlink&oid=6517959

+ Details

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