Consolidated Statements of Capital (Unaudited) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Stock based compensation expense		$ 1,346,155
Net income attributable to Retail Opportunity Investments Partnership, LP	2,471,012	4,760,898
Other comprehensive gain		8,432,564
General Partner's Capital [Member] | Retail Opportunity Investments Partnership L.P. [Member]
Balance	667,790,208	667,790,208	484,694,294
Distributions to ROIC		(43,382,505)
Contributions from ROIC		220,371,366
Stock based compensation expense		1,346,155
Net income attributable to Retail Opportunity Investments Partnership, LP		4,760,898
Accumulated Other Comprehensive Income (Loss) [Member] | Retail Opportunity Investments Partnership L.P. [Member]
Balance	(9,722,048)	(9,722,048)	(18,154,612)
Other comprehensive gain		8,432,564
Accumulated Other Comprehensive Income (Loss) [Member]
Other comprehensive gain		8,432,564
Noncontrolling Interest [Member] | Retail Opportunity Investments Partnership L.P. [Member]
Balance	2,389	2,389	2,389
Additional Paid-in Capital [Member] | Retail Opportunity Investments Partnership L.P. [Member]
Balance	658,070,549	658,070,549	466,542,071
Distributions to ROIC		(43,382,505)
Contributions from ROIC		220,371,366
Stock based compensation expense		1,346,155
Net income attributable to Retail Opportunity Investments Partnership, LP		4,760,898
Other comprehensive gain		8,432,564
Additional Paid-in Capital [Member]
Stock based compensation expense		1,346,155
Retail Opportunity Investments Partnership L.P. [Member]
Balance	667,790,208	667,790,208	484,694,294
Distributions to ROIC		(43,327,505)
Contributions from ROIC		(220,371,366)
Net income attributable to Retail Opportunity Investments Partnership, LP	$ 2,471,012	$ 4,760,898