Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012
Commitments and Contingencies [Abstract]
Amount Of Contingent Payments For Tenant Improvements And Leasing Costs	$ 1.4
Amount of Commitments for Construction Contracts Over Next Twelve Months	$ 9.8

The amount of contingent payments for tenant improvements and leasing costs for the entity at date of balance sheet.

No definition available.

Name:	o_TenantImprovementsAndLeasingCostsContingentPayments
Namespace Prefix:	o_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant