Consolidated Statement of Partners' Capital - 9 months ended Sep. 30, 2018 - USD ($) $ in Thousands		Total	Officer	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]							387,861
OP Units issued under the Equity Incentive Plan				145				$ 145	[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]							(6,999)
Cancellation of OP Units				0				$ 0	[2]
Stock based compensation expense		5,415		5,415				5,415	[2]
Cash redemption of OP Units (in units)	[1]					(104,950)
Cash redemption of OP Units		1,992		(1,992)		$ (1,992)	[1]
Adjustment to non-controlling interests ownership in Operating Partnership						2,529	[1]	$ (2,529)	[2]
Issuance of OP Units in connection with sale of common stock (in shares)	[2]							1,326,690
Issuance of OP Units in connection with sale of common stock		25,703		25,703				$ 25,703	[2]
Registration expenditures		(376)		(376)				(376)	[2]
Cash distributions ($0.5850 per unit)				(73,003)		(6,815)	[1]	(66,188)	[2]
Dividends payable to officers		(73,003)	$ (247)		$ (247)					$ (247)
Net income attributable to Retail Opportunity Investments Partnership, LP		35,573		35,573		$ 3,338	[1]	$ 32,235	[2]
Other comprehensive income		$ 6,124		6,124								6,124
Balance (in shares) at Sep. 30, 2018		125,558,876				11,574,041	[1]	113,984,835	[2]
Balance at Sep. 30, 2018				$ 1,325,583		$ 122,734	[1]	$ 1,194,869	[2]			$ 7,980

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

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