Capital of the Operating Partnership (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Capital of Operating Partnership [Line Items]
Partnership units ( in shares)		131,227,363
Shares outstanding (in shares)		122,685,266	118,085,155
Notices of redemptions received (in shares)		423,986
Equity Redemption of OP Units (in shares)		423,986
Common Stock
Capital of Operating Partnership [Line Items]
Shares outstanding (in shares)		122,685,266	118,085,155	116,496,016	113,992,837
Equity Redemption of OP Units (in shares)		423,986	1,968,350	143,190
OP Units
Capital of Operating Partnership [Line Items]
Non-controlling interest redemption value		$ 162.0
Non-controlling interest redemption value (in usd per share)		$ 18.96
Retail Opportunity Investments Partnership L.P.
Capital of Operating Partnership [Line Items]
ROIC ownership percentage in ROIP LP		93.50%
Retail Opportunity Investments Partnership L.P. | Limited Partner’s Capital
Capital of Operating Partnership [Line Items]
Partnership units ( in shares)	[1]	8,542,097	8,966,083	11,051,090	11,477,041
Equity Redemption of OP Units (in shares)	[1]	423,986	1,968,350	143,190

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