Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012
Commitments and Contingencies.
Amount of contingent payments for tenant improvements and leasing costs	$ 2.8
Amount of commitments for construction contracts, which is expected to be paid in next six months	$ 9.9

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