Noncontrolling Interests (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 31, 2015 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) shares	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) shares	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($) shares	Jun. 27, 2013 shares	Jan. 22, 2013 shares
Noncontrolling interests
Conversion ratio				1
Change in the carrying value of all noncontrolling interests
Carrying value at beginning of the period	$ 27,698			$ 27,698	$ 35,911	$ 35,911
Reallocation of equity				(1,051)		(6,647)
Redemptions				(2,121)		(1,032)
Distributions				(1,257)		(1,839)
Allocation of net income		$ 338	$ 344	919	1,016	1,305
Carrying value at end of the period		$ 24,188		$ 24,188		27,698
Carrying value of preferred units						6,750
Tau Operating Partnership, L.P.
Noncontrolling interests
Realty Income partnership units, ownership interest (as a percent)		99.40%		99.40%
Change in the carrying value of all noncontrolling interests
Carrying value at beginning of the period	$ 13,067			$ 13,067	13,489	13,489
Reallocation of equity				836
Distributions				(541)		(695)
Allocation of net income				195		273
Carrying value at end of the period		$ 13,557		$ 13,557		$ 13,067
Units held by third party | shares		317,022		317,022		317,022		317,022
Payment rate per annum (as a percent)						2.00%
Partnership preferred units redeemed (in shares) | shares	6,750
Partnership preferred units redemption price (in dollars per unit) | $ / shares	$ 1,000
Realty Income, L.P.
Noncontrolling interests
Third party partnership units, ownership interest (as a percent)		1.70%		1.70%
Realty Income partnership units, ownership interest (as a percent)		98.30%		98.30%
Change in the carrying value of all noncontrolling interests
Carrying value at beginning of the period	$ 14,631			$ 14,631	$ 22,422	$ 22,422
Reallocation of equity				(1,887)		(6,647)
Redemptions				(2,121)		(1,032)
Distributions				(716)		(1,144)
Allocation of net income				724		1,032
Carrying value at end of the period		$ 10,631		$ 10,631		$ 14,631
Units held by third party | shares		419,546		419,546		499,546	534,546