Impairments (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($) property	Sep. 30, 2015 USD ($) property	Sep. 30, 2016 USD ($) property	Sep. 30, 2015 USD ($) property
Impairments
Total Provisions for impairment | $	$ 8.8	$ 3.9	$ 17.0	$ 9.2
Number of impaired properties sold	11	3	23	8
Number of impaired properties held-for-sale	5		7
Number of impaired properties held-for-investment	2	1	2	3
Number of impaired properties disposed from other than sale				1
Automotive parts
Impairments
Number of properties impaired			1
automotive service industry
Impairments
Number of properties impaired	1		2
Automotive tire service industry
Impairments
Number of properties impaired	1		1
Convenience stores
Impairments
Number of properties impaired			1
Financial services industry
Impairments
Number of properties impaired	1		1
Furniture Stores
Impairments
Number of properties impaired			1
General merchandise industry
Impairments
Number of properties impaired	1		1
Health and fitness
Impairments
Number of properties impaired			1	1
Restaurants - casual dining industry
Impairments
Number of properties impaired	13	3	19	9
restaurant-quick service industry
Impairments
Number of properties impaired			1
Other non-reportable segments
Impairments
Number of properties impaired	1		3	1
Pet supplies and services
Impairments
Number of properties impaired		1		1