Real Estate Investments (Details) - Pro Forma Financial Information - Results of Operations Had the Acquisitions Occurred at the Beginning of the Year $ in Thousands	12 Months Ended
Dec. 31, 2016 USD ($)
Business Combinations [Abstract]
Revenues	$ 245,116
Net income attributable to Retail Opportunity Investments Corp.	$ 33,169

The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)-(3)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

Name:	us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration