Organization, Basis of Presentation and Summary of Significant Accounting Policies - Reconciliation Between Basic and Diluted EPS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net income	$ 12,466	$ 7,974
Less income attributable to non-controlling interests	(825)	(559)
Less earnings allocated to unvested shares	(88)	(77)
Net income available for common stockholders, basic	11,553	7,338
Less earnings allocated to unvested shares	(88)	(77)
Net income available for common stockholders, diluted	$ 12,378	$ 7,897
Denominator:
Denominator for basic EPS – weighted average common equivalent shares (in shares)	122,410,238	117,740,165
Denominator for diluted EPS – weighted average common equivalent shares (in shares)	131,438,668	126,873,836
Retail Opportunity Investments Partnership L.P.
Numerator:
Net income	$ 12,466	$ 7,974
Less earnings allocated to unvested shares	(88)	(77)
Net income available to unitholders, basic and diluted	$ 12,378	$ 7,897
Denominator:
Denominator for basic EPS – weighted average common equivalent shares (in shares)	131,106,973	126,653,782
Denominator for diluted EPS – weighted average common equivalent shares (in shares)	131,438,668	126,873,836
OP Units
Denominator:
OP Units (in shares)	8,696,735	8,913,617
Performance-based restricted stock awards
Denominator:
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	330,337	214,625
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)	330,337	214,625
Stock options
Denominator:
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	1,358	5,429
Stock options | Retail Opportunity Investments Partnership L.P.
Denominator:
Incremental common shares attributable to dilutive effect of share-based payment arrangements (in shares)	1,358	5,429