Capital of the Operating Partnership (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended					9 Months Ended
		Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Limited Partners' Capital Account [Line Items]
Partnership units (in shares)		132,988,735					132,988,735
Common stock, shares outstanding (in shares)		124,541,618					124,541,618	122,685,266
Minority interest increase (decrease) from redemptions number of units (in shares)							296,840
Equity Redemption of OP Units (in shares)							296,840
ROIC
Limited Partners' Capital Account [Line Items]
ROIC ownership percentage in ROIP LP							93.60%
Common Stock
Limited Partners' Capital Account [Line Items]
Common stock, shares outstanding (in shares)		124,541,618	124,341,618	123,732,344	120,806,366	118,577,713	124,541,618	122,685,266	121,423,616	118,085,155
Equity Redemption of OP Units (in shares)		200,000	46,840	50,000	325,000	98,986	296,840
OP Units
Limited Partners' Capital Account [Line Items]
Non-controlling interest redemption value		$ 124.5					$ 124.5
Redemption value (usd per share)		$ 14.74					$ 14.74
Retail Opportunity Investments Partnership L.P.
Limited Partners' Capital Account [Line Items]
Equity Redemption of OP Units (in shares)		200,000
Limited Partner’s Capital | Retail Opportunity Investments Partnership L.P.
Limited Partners' Capital Account [Line Items]
Partnership units (in shares)	[1]	8,447,117	8,647,117	8,693,957	8,542,097	8,867,097	8,447,117	8,542,097	8,542,097	8,966,083
Equity Redemption of OP Units (in shares)	[1]	200,000	(46,840)	(50,000)	(325,000)	(98,986)

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