Consolidated Statements of Equity (unaudited) (USD $)	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2012	$ 5,260	$ 523,540,268	$ (38,851,234)	$ (18,154,612)	$ 2,389	$ 466,542,071
Balance (in Shares) at Dec. 31, 2012	52,596,754					52,596,754
Shares issued under the 2009 Plan	19	(19)
Shares issued under the 2009 Plan (in Shares)	191,414
Repurchase of common stock	(2)	(280,972)				(280,974)
Repurchase of common stock (in Shares)	(21,865)
Retirement of options		(268,550)				(268,550)
Stock based compensation expense		596,220				596,220
Proceeds from the exercise of warrants	1,290	155,468,124				155,469,414
Proceeds from the exercise of warrants (in Shares)	12,955,785
Exercise of Sponsor warrants	68	(68)
Exercise of Sponsor warrants (in Shares)	688,500
Buyback of warrants		(10,687,500)				(10,687,500)
Registration expenditures		(25,305)				(25,305)
Dividends ($.15 per share)			(9,896,866)			(9,896,866)
Dividends payable on performance-based shares			(27,500)			(27,500)
Net Income Attributable to Retail Opportunity Investments Corp.			2,289,886			2,289,886
Other comprehensive gain				1,519,938		1,519,938
Balance at Mar. 31, 2013	$ 6,635	$ 668,342,198	$ (46,485,714)	$ (16,634,674)	$ 2,389	$ 605,230,834
Balance (in Shares) at Mar. 31, 2013	66,410,588					66,410,588