Description of Business (Details)	Dec. 31, 2018 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	129
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
Triple Net Leased Properties
Real estate properties
Number of real estate properties	442
Triple Net Leased Properties | Ardent
Real estate properties
Number of real estate properties	10
Development Projects
Real estate properties
Number of real estate properties	19
Development Projects | Unconsolidated Real Estate Entities
Real estate properties
Number of real estate properties	5
Seniors Housing Communities
Real estate properties
Number of independent third party managed properties	359