Capital of the Operating Partnership (Details Textual) $ / shares in Units, $ in Millions		9 Months Ended
		Sep. 30, 2017 USD ($) $ / shares shares	Dec. 31, 2016 shares
Limited Partners' Capital Account [Line Items]
Partnership units (in shares)	[1]	121,409,187
Limited Partnership (LP), ownership interest ( percentage)		90.30%
Equity, redemption basis		1
Redemption price, threshold consecutive trading days (days)		10 days
OP Unit redemption (in shares)		157,567
Conversion of Stock, Shares Issued		150,503
Equity redemption of OP Units (shares)		7,064
OP Units
Limited Partners' Capital Account [Line Items]
Non-controlling interest redemption value | $		$ 224.0
Redemption value (usd per share) | $ / shares		$ 19.18
ROIC Capital | Retail Opportunity Investments Partnership L.P.
Limited Partners' Capital Account [Line Items]
Partnership units (in shares)	[1]	109,730,196.000	109,301,762
OP Unit redemption (in shares)	[1]	150,503
Limited Partner’s Capital | Retail Opportunity Investments Partnership L.P.
Limited Partners' Capital Account [Line Items]
Partnership units (in shares)	[2]	11,678,991.000	11,668,061
OP Unit redemption (in shares)	[2]	(150,503)

[1] Consists of general and limited partnership interests held by ROIC.

[2] Consists of limited partnership interests held by third parties.