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 income
Balance (in shares) at Dec. 31, 2017					11,678,991	[1]	112,347,451	[2]
Balance at Dec. 31, 2017			$ 1,329,641		$ 125,674	[1]	$ 1,202,111	[2]			$ 1,856
Increase (Decrease) in Partners' Capital [Roll Forward]
OP units issued under the Equity Incentive Plan (in shares)	[2]						373,861
OP Units issued under the Equity Incentive Plan		$ 0	0				$ 0	[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]						(4,999)
Cancellation of OP Units			0				$ 0	[2]
Stock based compensation expense		1,428	1,428				1,428	[2]
Adjustment to non-controlling interests ownership in Operating Partnership					191	[1]	$ (191)	[2]
Issuance of OP Units in connection with sale of common stock (in shares)	[2]						75,314
Issuance of OP Units in connection with sale of common stock		1,508	1,508				$ 1,508	[2]
Registration expenditures		(48)	(48)				(48)	[2]
Cash distributions			(24,258)	$ (72)	(2,277)	[1]	(21,981)	[2]	$ (72)
Net income attributable to Retail Opportunity Investments Partnership, LP		11,824	11,824		$ 1,122	[1]	$ 10,702	[2]
Other comprehensive income (loss)		3,808	3,808								3,808
Balance (in shares) at Mar. 31, 2018					11,678,991	[1]	112,721,459	[2]
Balance at Mar. 31, 2018			1,322,431		$ 124,710	[1]	$ 1,192,057	[2]			5,664
Balance (in shares) at Dec. 31, 2018					11,477,041	[1]	113,992,837	[2]
Balance at Dec. 31, 2018			1,308,428		$ 120,214	[1]	$ 1,184,653	[2]			3,561
Increase (Decrease) in Partners' Capital [Roll Forward]
OP units issued under the Equity Incentive Plan (in shares)	[2]						445,022
OP Units issued under the Equity Incentive Plan		0	0				$ 0	[2]
OP Units withheld for employee taxes (in shares)	[2]						(125,072)
OP Units withheld for employee taxes		(1,986)	(1,986)				$ (1,986)	[2]
Cancellation of OP Units (in shares)	[2]						(999)
Cancellation of OP Units			0				$ 0	[2]
Stock based compensation expense		1,651	1,651				1,651	[2]
Cash redemption of OP Units (in units)	[1]				(70,000)
Cash redemption for non-controlling interests		(1,246)	(1,246)		$ (1,246)	[1]
Adjustment to non-controlling interests ownership in Operating Partnership					(56)	[1]	56	[2]
Registration expenditures		(47)	(47)				(47)	[2]
Cash distributions			(24,766)	$ 142	(2,247)	[1]	(22,519)	[2]	$ 142
Net income attributable to Retail Opportunity Investments Partnership, LP		14,583	14,583		$ 1,333	[1]	$ 13,250	[2]
Other comprehensive income (loss)		$ (2,810)	(2,810)								(2,810)
Balance (in shares) at Mar. 31, 2019		125,718,829			11,407,041	[1]	114,311,788	[2]
Balance at Mar. 31, 2019			$ 1,293,949		$ 117,998	[1]	$ 1,175,200	[2]			$ 751

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

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