Gain on Sales of Investment Properties (Details) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Gain on Sales of Investment Properties [Abstract]
Investment property sales (by property)	6	7	9	10
Sales proceeds from investment properties	$ 3,300,000		$ 4,400,000
Gain (Loss) on sales of investment properties	1,100,000		1,200,000
Sales proceeds from excess land	675,000
Gain (Loss) on sales of excess land	155,000		(155,000)	0
Sales proceeds from investment properties and excess land		6,000,000		7,800,000
Gain (Loss) on sales of investment properties and excess land		$ 1,700,000		$ 2,400,000

The difference between the carrying value and the sale price of excess land properties that were a part of core operations. This element refers to the gain(loss) included and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

Name:	o_GainLossOnSaleOfExcessLand
Namespace Prefix:	o
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The difference between the carrying value and the sale price of investment properties and excess land. This element refers to the gain(loss) included and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ Details

Name:	o_GainLossOnSalesOfInvestmentPropertiesAndExcessLand
Namespace Prefix:	o
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of sales of real estate properties held for investment, that is, it is part of an investing activity during the period.

+ Details

Name:	o_InvestmentPropertySalesCount
Namespace Prefix:	o
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Cash received from the sale of real estate held for investment and excess land that were a part of core operations.

+ Details

Name:	o_ProceedsFromSaleOfRealEstateHeldForInvestmentAndExcessLand
Namespace Prefix:	o
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Cash received from the sale of investment properties and excess land.

+ Details

Name:	o_SalesProceedsFromInvestmentPropertiesAndExcessLand
Namespace Prefix:	o
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_GainLossOnSaleOfInvestmentsAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
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- Definition

The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainLossOnSaleOfProperties
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow associated with the sale of other real estate not otherwise defined in the taxonomy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 16
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromSaleOfOtherRealEstate
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration