Organization, Basis of Presentation and Summary of Significant Accounting Policies - Reconciliation Between Basic and Diluted EPS (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Net income	$ 12,314		$ 17,685		$ 24,780	$ 25,659
Less income attributable to non-controlling interests	(807)	$ (825)	(1,201)	$ (559)	(1,632)	(1,760)
Less earnings allocated to unvested shares	(88)		(77)		(176)	(154)
Net income available for common stockholders, basic	11,419		16,407		22,972	23,745
Less earnings allocated to unvested shares	(88)		(77)		(176)	(154)
Net income available for common stockholders, diluted	$ 12,226		$ 17,608		$ 24,604	$ 25,505
Denominator:
Denominator for basic EPS – weighted average common equivalent shares (in shares)	123,537,494		118,532,188		122,976,980	118,138,364
Denominator for diluted EPS – weighted average common equivalent shares (in shares)	132,580,586		127,467,340		132,041,664	127,191,040
Retail Opportunity Investments Partnership L.P.
Numerator:
Net income	$ 12,314	$ 12,466	$ 17,685	$ 7,974	$ 24,780	$ 25,659
Less earnings allocated to unvested shares	(88)		(77)		(176)	(154)
Net income available to unitholders, basic and diluted	$ 12,226		$ 17,608		$ 24,604	$ 25,505
Denominator:
Denominator for basic EPS – weighted average common equivalent shares (in shares)	132,200,567		127,141,593		131,656,791	126,899,035
Denominator for diluted EPS – weighted average common equivalent shares (in shares)	132,580,586		127,467,340		132,041,664	127,191,040
OP Units
Denominator:
OP Units (in shares)	8,663,073		8,609,405		8,679,811	8,760,671
Performance-based restricted stock awards
Denominator:
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	378,819		317,263		383,592	284,919
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)	378,819		317,263		383,592	284,919
Stock options
Denominator:
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	1,200		8,484		1,281	7,086
Stock options | Retail Opportunity Investments Partnership L.P.
Denominator:
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	1,200		8,484		1,281	7,086