Organization, Basis of Presentation and Summary of Significant Accounting Policies - Reconciliation Between Basic and Diluted EPS (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Numerator:
Net income	$ 19,786			$ 22,589			$ 44,566	$ 48,248
Less income attributable to non-controlling interests	(1,264)	$ (807)	$ (825)	(1,494)	$ (1,201)	$ (559)	(2,896)	(3,254)
Less earnings allocated to unvested shares	(102)			(76)			(278)	(230)
Net income available for common stockholders, basic	18,420			21,019			41,392	44,764
Less earnings allocated to unvested shares	(102)			(76)			(278)	(230)
Net income available for common stockholders, diluted	$ 19,684			$ 22,513			$ 44,288	$ 48,018
Denominator:
Denominator for basic EPS – weighted average common equivalent shares (in shares)	123,797,859			120,624,862			123,253,613	118,976,305
Denominator for diluted EPS – weighted average common equivalent shares (in shares)	132,738,470			129,540,160			132,354,492	128,012,343
Retail Opportunity Investments Partnership L.P.
Numerator:
Net income	$ 19,786	$ 12,314	$ 12,466	$ 22,589	$ 17,685	$ 7,974	$ 44,566	$ 48,248
Less earnings allocated to unvested shares	(102)			(76)			(278)	(230)
Net income available to unitholders, basic and diluted	$ 19,684			$ 22,513			$ 44,288	$ 48,018
Denominator:
Denominator for basic EPS – weighted average common equivalent shares (in shares)	132,260,193			129,166,959			131,860,135	127,663,317
Denominator for diluted EPS – weighted average common equivalent shares (in shares)	132,738,470			129,540,160			132,354,492	128,012,343
OP Units
Denominator:
OP Units (in shares)	8,462,334			8,542,097			8,606,522	8,687,012
Performance-based restricted stock awards
Denominator:
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	477,364			364,709			493,193	341,441
Performance-based restricted stock awards | Retail Opportunity Investments Partnership L.P.
Denominator:
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	477,364			364,709			493,193	341,441
Stock options
Denominator:
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	913			8,492			1,164	7,585
Stock options | Retail Opportunity Investments Partnership L.P.
Denominator:
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	913			8,492			1,164	7,585