Mortage Backed Securities - Pledged Securities - Narrative (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Securities Pledged As Collateral [Abstract]
Unpledged Mortgage Backed Securities	$ 53,804,610	$ 5,775,015
Unsettled Securities Purchases Included in Unpledged Securities	$ 38,800,000	$ 0

Investments in mortgage backed securities for which the Fair Value Option has been elected that are unencumbered at the balance sheet date. Such securities are reported at fair value; gains (losses) are included in earnings.

No definition available.

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