Note 2 - Real Estate Investments (Details) - Operating Results Included in the Company's Historical Consolidated Statement of Operations For Properties Acquired During the Reported Periods (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement of operations:
Revenues	$ 26,062,207	$ 18,118,372	$ 50,446,656	$ 34,766,056
Property operating and other expenses	4,081,626	3,282,120	8,240,507	6,251,468
Depreciation and amortization	9,176,706	7,017,542	18,057,836	13,667,360
Net income attributable to Retail Opportunity Investments Corp.	2,471,012	4,424,752	4,760,898	5,552,156
Attributable to Acquired Properties During the Reporting Periods [Member]
Statement of operations:
Revenues	2,008,856		2,563,517
Property operating and other expenses	970,464		1,235,863
Depreciation and amortization	991,266		1,260,183
Net income attributable to Retail Opportunity Investments Corp.	$ 47,126		$ 67,471