Note 2 - Real Estate Investments (Details) - Pro Forma Financial Information - Results of Operations Had the Acquisitions Occured at the Beginning of the Year (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Pro Forma Financial Information - Results of Operations Had the Acquisitions Occured at the Beginning of the Year [Abstract]
Revenues	$ 171,900,319	$ 169,032,796
Property operating and other expenses	83,532,767	59,987,450
Depreciation and amortization	64,650,002	64,885,935
Net income attributable to Retail Opportunity Investments Corp.	$ 23,717,550	$ 44,159,411