Noncontrolling Interests (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018 USD ($) shares	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) shares	Jun. 30, 2017 USD ($)	Dec. 31, 2016 entity property	Apr. 30, 2018 shares	Mar. 30, 2018 shares	Dec. 31, 2017 shares	Jun. 27, 2013 shares	Jan. 31, 2013	Jan. 22, 2013 shares
Noncontrolling interests
Conversion ratio			1
Number of properties acquired | property					2
Number of joint ventures controlling interest acquired | entity					2
Change in the carrying value of all noncontrolling interests
Carrying value at beginning of the period			$ 19,207
Reallocation of equity			492
Redemptions			(1,468)
Shares issued in conjunction with acquisition			18,848
Distributions			(829)
Allocation of net income	$ 317	$ 123	469	$ 288
Carrying value at end of the period	$ 36,719		$ 36,719
Joint Venture One
Noncontrolling interests
Ownership interest (as a percent)	95.00%		95.00%
Joint Venture Two
Noncontrolling interests
Ownership interest (as a percent)	74.00%		74.00%
Tau Operating Partnership
Noncontrolling interests
Realty Income partnership units, ownership interest (as a percent)										99.40%
Change in the carrying value of all noncontrolling interests
Carrying value at beginning of the period			$ 13,322
Reallocation of equity			572
Redemptions			0
Shares issued in conjunction with acquisition			0
Distributions			(417)
Allocation of net income			173
Carrying value at end of the period	$ 13,650		$ 13,650
Number of partnership units outstanding | shares	317,022		317,022					317,022
Number of partnership units issued | shares											317,022
Realty Income, L.P.
Noncontrolling interests
Realty Income partnership units, ownership interest (as a percent)	98.40%		98.40%
Third party partnership units, ownership interest (as a percent)	1.60%		1.60%
Change in the carrying value of all noncontrolling interests
Carrying value at beginning of the period			$ 2,160
Reallocation of equity			(43)
Redemptions			(1,468)
Shares issued in conjunction with acquisition			18,848
Distributions			(336)
Allocation of net income			257
Carrying value at end of the period	$ 19,418		$ 19,418
Number of partnership units outstanding | shares	401,979		401,979					88,182
Number of partnership units issued | shares	373,797		373,797			131,790	242,007		534,546
Other Noncontrolling Interests
Change in the carrying value of all noncontrolling interests
Carrying value at beginning of the period			$ 3,725
Reallocation of equity			(37)
Redemptions			0
Distributions			(76)
Allocation of net income			39
Carrying value at end of the period	$ 3,651		$ 3,651