Significant Accounting Policies - Repurchase Agreements (Details) (USD $)	Mar. 31, 2013
Significant Accounting Policies [Abstract]
Repurchase Agreement Amount At Risk	$ 17,700,000

The total amount at risk with all repurchase agreement counterparties at the end of the period. The amount at risk isthe difference between the amount loaned to the Company, including interest payable, and the fair value of the collateral pledged by the Company, including accrued interest and cash posted as collateral

No definition available.

Name:	orc_RepurchaseAgreementAmountAtRisk
Namespace Prefix:	orc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant