Note 2 - Real Estate Investments (Details) - Pro Forma Financial Information - Results of Operations Had the Acquisitions Occured at the Beginning of the Year (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement of operations:
Revenues	$ 26,331,595	$ 25,180,449	$ 51,065,929	$ 47,497,162
Property operating and other expenses	15,229,803	9,599,694	29,333,089	21,847,747
Depreciation and amortization	9,210,852	9,434,100	18,249,685	17,741,075
Net income attributable to Retail Opportunity Investments Corp.	$ 1,890,940	$ 6,146,655	$ 3,483,155	$ 7,908,340