Consolidated Statement of Partners' Capital - USD ($) $ in Thousands		Total	Retail Opportunity Investments Partnership L.P.	Retail Opportunity Investments Partnership L.P. Officer	Retail Opportunity Investments Partnership L.P. Limited Partner’s Capital		Retail Opportunity Investments Partnership L.P. ROIC Capital		Retail Opportunity Investments Partnership L.P. ROIC Capital Officer	[2]	Retail Opportunity Investments Partnership L.P. Accumulated other comprehensive (loss) income
Total (in shares)					12,195,603	[1]	99,531,034	[2]
Balance (in shares) at Dec. 31, 2015					12,195,603	[1]	99,531,034	[2]
Balance at Dec. 31, 2015			$ 1,131,342		$ 94,671	[1]	$ 1,043,414	[2]			$ (6,743)
OP Units issued under the 2009 Equity Incentive Plan (in shares)	[2]						341,306
OP Units withheld for employee taxes (in shares)	[2]						(76,262)
OP Units withheld for employee taxes		$ (1,368)	(1,368)				$ (1,368)	[2]
Cancellation of OP Units (in shares)	[2]						(7,332)
Stock based compensation expense		4,916	4,916				$ 4,916	[2]
Issuance of OP Units in connection with acquisition (in shares)	[1]				2,434,833
Issuance of OP Units in connection with acquisition			48,175		$ 48,175	[1]
Equity redemption of OP Units (in shares)					(755,762)	[1]	755,762	[2]
Equity redemption of OP Units		15,990			$ (15,990)	[1]	$ 15,990	[2]
Cash redemption of OP Units (in shares)	[1]				(2,206,613)
Cash redemption of OP Units		(7,182)	(7,182)		$ (7,182)	[1]
Adjustment to non-controlling interests ownership in Operating Partnership					5,627	[1]	$ (5,627)	[2]
Issuance of OP Units in connection with common stock offering (in shares)	[2]						8,757,254
Issuance of OP Units in connection with common stock offering		184,881	184,881				$ 184,881	[2]
Registration expenditures		(7,276)	(7,276)				(7,276)	[2]
Cash distributions			(83,900)	$ (177)	(8,363)	[1]	(75,537)	[2]	$ (177)
Net income		36,430	36,430		$ 3,676	[1]	$ 32,754	[2]
Other comprehensive income		3,014	3,014								3,014
Total (in shares)					12,195,603	[1]	99,531,034	[2]
Total			1,308,855		$ 120,614	[1]	$ 1,191,970	[2]			(3,729)
Proceeds from repayment of promissory note receivable secured by capital		6,710	6,710		$ 6,710	[1]
Balance (in shares) at Dec. 31, 2016					11,668,061	[1]	109,301,762	[2]
Balance at Dec. 31, 2016			1,315,565		$ 127,324	[1]	$ 1,191,970	[2]			(3,729)
Total (in shares)					11,668,061	[1]	109,301,762	[2]
OP Units issued under the 2009 Equity Incentive Plan (in shares)	[2]						353,261
OP units issued under the 2009 Equity Incentive Plan		44	44				$ 44	[2]
OP Units withheld for employee taxes (in shares)	[2]						(74,331)
OP Units withheld for employee taxes		(1,571)	(1,571)				$ (1,571)	[2]
Cancellation of OP Units (in shares)	[2]						(1,999)
Stock based compensation expense		6,190	6,190				$ 6,190	[2]
Issuance of OP Units in connection with acquisition (in shares)	[1]				2,573,927
Issuance of OP Units in connection with acquisition			49,599		$ 49,599	[1]
Equity redemption of OP Units (in shares)					(2,555,933)	[1]	2,555,933	[2]
Equity redemption of OP Units		50,155			$ (50,155)	[1]	$ 50,155	[2]
Cash redemption of OP Units (in shares)	[1]				(7,064)
Cash redemption of OP Units		(150)	(150)		$ (150)	[1]
Adjustment to non-controlling interests ownership in Operating Partnership					3,574	[1]	$ (3,574)	[2]
Issuance of OP Units in connection with common stock offering (in shares)	[2]						212,825
Issuance of OP Units in connection with common stock offering		4,481	4,481				$ 4,481	[2]
Registration expenditures		(1,045)	(1,045)				(1,045)	[2]
Cash distributions			(91,510)	(235)	(8,729)	[1]	(82,781)	[2]	(235)
Net income		42,688	42,688		$ 4,211	[1]	$ 38,477	[2]
Other comprehensive income		5,585	5,585								5,585
Total (in shares)					11,668,061	[1]	109,301,762	[2]
Balance (in shares) at Dec. 31, 2017					11,678,991		112,347,451
Balance at Dec. 31, 2017			1,329,641		$ 125,674		$ 1,202,111				1,856
Total (in shares)					11,678,991		112,347,451
OP Units issued under the 2009 Equity Incentive Plan (in shares)	[2]						397,861
OP units issued under the 2009 Equity Incentive Plan		269	269				$ 269	[2]
OP Units withheld for employee taxes (in shares)	[2]						(70,168)
OP Units withheld for employee taxes		(1,400)	(1,400)				$ (1,400)	[2]
Cancellation of OP Units (in shares)	[2]						(8,997)
Stock based compensation expense		7,392	7,392				$ 7,392	[2]
Equity redemption of OP Units		$ 0
Cash redemption of OP Units (in shares)		(201,950)			(201,950)	[1]
Cash redemption of OP Units		$ (3,713)	(3,713)		$ (3,713)	[1]
Adjustment to non-controlling interests ownership in Operating Partnership					2,904	[1]	$ (2,904)	[2]
Issuance of OP Units in connection with common stock offering (in shares)	[2]						1,326,690
Issuance of OP Units in connection with common stock offering		25,703	25,703				$ 25,703	[2]
Registration expenditures		(570)	(570)				(570)	[2]
Cash distributions			(97,473)	$ (267)	(9,056)	[1]	(88,417)	[2]	$ (267)
Net income		47,141	47,141		$ 4,405	[1]	$ 42,736	[2]
Other comprehensive income		$ 1,705	1,705								1,705
Total (in shares)		125,469,878			11,678,991		112,347,451
Balance (in shares) at Dec. 31, 2018		125,469,878			11,477,041		113,992,837
Balance at Dec. 31, 2018			$ 1,308,428		$ 120,214		$ 1,184,653				$ 3,561
Total (in shares)		125,469,878			11,477,041		113,992,837

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

[2] Consists of general and limited partnership interests held by ROIC.