Mortgages Payable (Details) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2014 item	Sep. 30, 2013	Dec. 31, 2013 item
Debt instrument
Assumed mortgages payable	$ 166,700,000	$ 81,300,000
Remaining balance of deferred financing costs at period end	24,381,000		21,323,000
Unamortized Premium Balance, net	(18,600,000)
Mortgage Payable Balance	862,212,000		783,360,000
Maturity mortgages payable, excluding net premiums
2015	150,000,000
2016	275,000,000
2017	175,000,000
2018	350,000,000
Thereafter	2,850,000,000
Totals	3,800,000,000
Minimum
Debt instrument
Weighted Average Stated Interest Rate (as a percent)	2.00%		2.50%
Weighted Average Effective Interest Rate (as a percent)	2.20%		2.40%
Maximum
Debt instrument
Weighted Average Stated Interest Rate (as a percent)	6.90%		6.90%
Weighted Average Effective Interest Rate (as a percent)	9.10%		9.20%
Mortgages Payable
Debt instrument
Amount repaid	77,600,000
Assumed mortgages payable	166,700,000
Assumed mortgages payable, non-recourse	152,000,000
Net discount (premiums) recorded upon assumption of mortgages	(604,000)	(28,400,000)
Remaining balance of deferred financing costs at period end	937,000		1,200,000
Deferred financing costs incurred		211,000
Number of Properties	243		227
Weighted Average Stated Interest Rate (as a percent)	5.00%		5.30%
Weighted Average Effective Interest Rate (as a percent)	4.00%		3.90%
Weighted Average Remaining Years Until Maturity	4 years		4 years 3 months 18 days
Remaining Principal Balance	843,600,000		754,508,000
Unamortized Premium Balance, net	18,612,000		28,852,000
Mortgage Payable Balance	862,212,000		783,360,000
Number of mortgages	58		47
Number of properties with mortgages	243		227
Maturity mortgages payable, excluding net premiums
2014	7,600,000
2015	119,700,000
2016	248,400,000
2017	142,500,000
2018	15,100,000
Thereafter	310,300,000
Totals	843,600,000
Mortgages repaid in full
Debt instrument
Amount repaid	72,000,000
Number of mortgages repaid	5
Mortgages, partial recourse
Debt instrument
Assumed mortgages payable	14,700,000
Assumed mortgages payable, non-recourse	11,500,000
Number of mortgages subject to partial recourse to Realty Income	2
Amount of principal subject to recourse to Realty Income	3,200,000
Variable rate mortgages
Debt instrument
Mortgage Payable Balance	$ 74,400,000		$ 31,100,000
Number of mortgages	5		2
Number of properties with mortgages	14