Credit Facility, Number of Extension Options

No definition available.

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Period Type:	instant

- Definition

Debt Instrument, Extension, Term

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Debt Instrument, Swapped Interest Rate

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents line of credit fronting fee.

+ References

No definition available.

+ Details

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Namespace Prefix:	roic_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

The amount of additional borrowing capacity under the term loan.

+ References

No definition available.

+ Details

Name:	roic_TermLoanAdditionalBorrowingCapacity
Namespace Prefix:	roic_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 210
-SubTopic 10
-Section S99
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The effective interest rate during the reporting period.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Mortgage Notes Payable, Credit Facilities and Senior Notes (Narrative) (Details)		12 Months Ended
	Dec. 20, 2019 USD ($) credit_facility_extension	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Nov. 10, 2017 USD ($)	Jul. 26, 2016 USD ($)	Dec. 03, 2014 USD ($)	Dec. 09, 2013 USD ($)
Revolving Credit Facility
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Line of credit facility, maximum borrowing capacity	$ 600,000,000.0
Number of extension options \| credit_facility_extension	2
Extension term	6 months
Line of credit facility, commitment fee (in percentage)		0.20%
Line of credit, fronting fee (in percentage)		0.125%
Credit facility		$ 84,000,000	$ 156,000,000
Line of credit facility, interest rate during period (in percentage)		3.30%
Remaining borrowing capacity		$ 516,000,000.0
Revolving Credit Facility \| Accordion Feature
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Line of credit facility, maximum borrowing capacity		$ 1,200,000,000
Federal Funds Effective Swap Rate \| Revolving Credit Facility
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Basis Spread on variable rate (in percentage)		0.50%
Eurodollar \| Revolving Credit Facility
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Basis Spread on variable rate (in percentage)		0.90%
Senior Notes
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Principal amount		$ 950,000,000
Term Loan Agreement
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Principal amount	$ 300,000,000.0	300,000,000	300,000,000
Additional borrowing capacity	$ 200,000,000.0
Long-term debt		$ 300,000,000.0
Interest rate during period (in percentage)		3.40%
Debt Instrument, Swapped Interest Rate		3.00%
Term Loan Agreement \| Federal Funds Effective Swap Rate
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Basis Spread on variable rate (in percentage)		0.50%
Term Loan Agreement \| Eurodollar
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Basis Spread on variable rate (in percentage)		1.00%
Senior Notes Due 2027 \| Senior Notes
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Principal amount		$ 250,000,000	250,000,000	$ 250,000,000.0
Interest Rate (in percentage)				4.19%
Senior Notes Due 2026 \| Senior Notes
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Principal amount		200,000,000	200,000,000		$ 200,000,000.0
Interest Rate (in percentage)					3.95%
Senior Notes Due 2024 \| Senior Notes
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Principal amount		250,000,000	250,000,000			$ 250,000,000.0
Interest Rate (in percentage)						4.00%
Senior Notes Due 2023 \| Senior Notes
Mortgage Notes Payable, Credit Facilities and Senior Notes [Line Items]
Principal amount		$ 250,000,000	$ 250,000,000				$ 250,000,000.0
Interest Rate (in percentage)							5.00%