Description of Business (Details)	Dec. 31, 2019 property tenant
Real estate properties
Number of real estate properties	1,200
Concentration risk, number of tenants | tenant	3
Brookdale Senior Living
Real estate properties
Number of real estate properties	122
Number of properties managed by large tenant excluded from property count for that tenant due to contract type	2
Ardent
Real estate properties
Number of real estate properties	11
Kindred
Real estate properties
Number of real estate properties	32
Development Projects
Real estate properties
Number of real estate properties	22
Development Projects | Unconsolidated Real Estate Entities
Real estate properties
Number of real estate properties	4
Triple Net Leased Properties
Real estate properties
Number of real estate properties	412
Seniors Housing Communities Managed by Independent Operators
Real estate properties
Number of real estate properties	406