Capital of the Operating Partnership (Details Textual) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
		Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Limited Partners' Capital Account [Line Items]
Partnership units (in shares)		127,055,137
Common stock, shares outstanding (in shares)		116,120,704	116,496,016
Minority interest increase (decrease) from redemptions number of units (in shares)		116,657
Equity redemption of OP Units, cash (in shares)		116,657
Equity redemption of OP Units cash dollars		$ 2.0
ROIC
Limited Partners' Capital Account [Line Items]
ROIC ownership percentage in ROIP LP		91.30%
Common Stock
Limited Partners' Capital Account [Line Items]
Common stock, shares outstanding (in shares)		116,120,704	116,496,016	114,311,788	113,992,837
OP Units
Limited Partners' Capital Account [Line Items]
Non-controlling interest redemption value		$ 90.2
Redemption value (usd per share)		$ 8.25
Limited Partner’s Capital | Retail Opportunity Investments Partnership L.P.
Limited Partners' Capital Account [Line Items]
Partnership units (in shares)	[1]	10,934,433	11,051,090	11,407,041	11,477,041

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