Real Estate Properties (Details) ft² in Thousands	1 Months Ended						6 Months Ended
	Jul. 31, 2017 USD ($) ft² building property	Jan. 31, 2017 ft²	Jan. 31, 2017 ft² living_unit	Jan. 31, 2017 ft² building	Jan. 31, 2017 USD ($) ft²	Jan. 31, 2017 ft² property	Jun. 30, 2017 USD ($) state building property
Real Estate Properties
Number of properties owned | property							434
Number of buildings owned | building							460
Number of states in which properties are located | state							42
Impairment of assets							$ 0
Acquisition
Real Estate Properties
Weighted average amortization period		10 years 3 months 18 days
Acquisition | MOBs | Kansas
Real Estate Properties
Number of properties			1			1
Number of buildings acquired | building				1
Area of real estate properties (in square feet) | ft²		117	117	117	117	117
Purchase price including closing costs and working capital adjustments					$ 15,106,000
Acquisition and certain other transaction related costs					$ 35,000
Subsequent Event | Acquisition | MOBs | MARYLAND
Real Estate Properties
Number of properties | property	1
Number of buildings acquired | building	1
Area of real estate properties (in square feet) | ft²	59
Purchase price excluding closing costs	$ 16,400,000
Scenario, Plan | Subsequent Event | Acquisition | MOBs | Minnesota
Real Estate Properties
Number of buildings acquired | building	1
Area of real estate properties (in square feet) | ft²	150
Purchase price excluding closing costs	$ 16,650,000