Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015
Commitments and Contingencies.
Amount of commitments for tenant improvements and leasing costs	$ 2
Amount of commitments for construction contracts, which is expected to be paid in next twelve months	$ 54.5

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