Capital of the Operating Partnership (Details Textual) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
		Mar. 31, 2018	Dec. 31, 2017
Limited Partners' Capital Account [Line Items]
Partnership units (in shares)		124,400,450
Limited Partnership (LP), ownership interest (percentage)		90.60%
Common stock, shares outstanding (in shares)		112,721,459	112,347,451
Common Stock
Limited Partners' Capital Account [Line Items]
Common stock, shares outstanding (in shares)		112,721,459	112,347,451
OP Units
Limited Partners' Capital Account [Line Items]
Non-controlling interest redemption value		$ 202.2
Redemption value (usd per share)		$ 17.31
Limited Partner’s Capital | Retail Opportunity Investments Partnership L.P.
Limited Partners' Capital Account [Line Items]
Partnership units (in shares)	[1]	11,678,991

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