Consolidated Statement of Partners' Capital - 3 months ended Mar. 31, 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	[2]	Retail Opportunity Investments Partnership L.P. ROIC Capital		Retail Opportunity Investments Partnership L.P. ROIC Capital Officer	[1]	Retail Opportunity Investments Partnership L.P. Accumulated other comprehensive loss	2009 stock plan Retail Opportunity Investments Partnership L.P. ROIC Capital
Balance (in shares) at Dec. 31, 2017	[1]							112,347,451
Balance at Dec. 31, 2017				$ 1,329,641		$ 125,674		$ 1,202,111	[1]			$ 1,856
Increase (Decrease) in Partners' Capital [Roll Forward]
OP units issued under the 2009 Plan (in shares)	[1]												373,861
OP Units withheld for employee taxes (in shares)	[1]							(70,168)
OP Units withheld for employee taxes		$ (1,400)		(1,400)				$ (1,400)	[1]
Cancellation of OP Units (in shares)	[1]							(4,999)
Cancellation of OP Units				0				$ 0	[1]
Stock based compensation expense		1,428		1,428				1,428	[1]
Adjustment to non-controlling interests ownership in Operating Partnership						191		$ (191)	[1]
Issuance of OP Units in connection with sale of common stock (in shares)	[1]							75,314
Issuance of OP Units in connection with sale of common stock		1,508		1,508				$ 1,508	[1]
Registration expenditures		(48)		(48)				(48)	[1]
Cash distributions ($0.1950 per unit)				(24,258)		(2,277)		(21,981)	[1]
Dividends payable to officers		(24,258)	$ (72)		$ (72)					$ (72)
Net income attributable to Retail Opportunity Investments Partnership, LP		11,824		11,824		$ 1,122		$ 10,702	[1]
Other comprehensive income		$ 3,808		3,808								3,808
Balance (in shares) at Mar. 31, 2018		124,400,450				11,678,991		112,721,459	[1]
Balance at Mar. 31, 2018				$ 1,322,431		$ 124,710		$ 1,192,057	[1]			$ 5,664

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

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