Real Estate Investments (Details) $ in Thousands									1 Months Ended	3 Months Ended	6 Months Ended
	Aug. 05, 2020 USD ($) ft²	Jul. 23, 2020 USD ($) ft²	Jul. 17, 2020 USD ($) ft²	Jul. 01, 2020 USD ($) ft²	Mar. 09, 2020 USD ($) ft² property	Feb. 25, 2020 USD ($) ft²	Feb. 13, 2020 USD ($) ft²	Jan. 03, 2020 USD ($) ft²	May 31, 2020 USD ($) property	Jun. 30, 2020 USD ($) ft² property	Jun. 30, 2020 USD ($) ft² land_parcel property	Jun. 30, 2019 USD ($)	Dec. 31, 2019 property
Business Acquisition [Line Items]
Number of land parcels acquired | land_parcel											4
Number of Properties Sold | property									2
Sales price									$ 244,500
Gains on sales of investment real estate										$ 68,300	$ 68,218	$ 4,865
Number of properties held for sale | property										0	0		0
Total real estate acquisitions
Business Acquisition [Line Items]
Purchase price											$ 102,000
Mortgage notes payable											(19,300)
Cash consideration											82,600
Real estate										$ 103,600	103,600
Other										$ (1,700)	$ (1,700)
Square footage | ft²										338,778	338,778
Land Acquisition
Business Acquisition [Line Items]
Purchase price											$ 1,600
Mortgage notes payable											0
Cash consideration											1,700
Real estate										$ 1,700	1,700
Other										$ 0	$ 0
Square footage | ft²										0	0
Real Estate and Land Acquisitions
Business Acquisition [Line Items]
Purchase price											$ 103,600
Mortgage notes payable											(19,300)
Cash consideration											84,300
Real estate										$ 105,300	105,300
Other										$ (1,700)	$ (1,700)
Square footage | ft²										338,778	338,778
Medical office building | Los Angeles, CA | Total real estate acquisitions
Business Acquisition [Line Items]
Purchase price								$ 42,000
Mortgage notes payable								(19,300)
Cash consideration								22,800
Real estate								42,400
Other								$ (300)
Square footage | ft²								86,986
Medical office building | Atlanta, GA | Total real estate acquisitions
Business Acquisition [Line Items]
Purchase price							$ 12,000
Mortgage notes payable							0
Cash consideration							11,800
Real estate							12,100
Other							$ (300)
Square footage | ft²							64,624
Medical office building | Raleigh, NC | Total real estate acquisitions
Business Acquisition [Line Items]
Purchase price						$ 6,300
Mortgage notes payable						0
Cash consideration						6,500
Real estate						6,500
Other						$ 0
Square footage | ft²						15,964
Medical office building | Colorado Springs, CO | Total real estate acquisitions
Business Acquisition [Line Items]
Purchase price					$ 8,200
Mortgage notes payable					0
Cash consideration					8,300
Real estate					8,600
Other					$ (300)
Square footage | ft²					34,210
Medical office building | Denver, CO | Total real estate acquisitions
Business Acquisition [Line Items]
Number of properties acquired | property					3
Purchase price					$ 33,500
Mortgage notes payable					0
Cash consideration					33,200
Real estate					34,000
Other					$ (800)
Square footage | ft²					136,994
Subsequent event | Medical office building | Total real estate acquisitions
Business Acquisition [Line Items]
Purchase price	$ 83,200
Square footage | ft²	165,322
Subsequent event | Medical office building | Los Angeles, CA | Total real estate acquisitions
Business Acquisition [Line Items]
Purchase price			$ 35,000
Square footage | ft²			49,785
Subsequent event | Medical office building | Atlanta, GA | Total real estate acquisitions
Business Acquisition [Line Items]
Purchase price		$ 20,500
Square footage | ft²		48,145
Subsequent event | Medical office building | San Diego, CA | Total real estate acquisitions
Business Acquisition [Line Items]
Purchase price				$ 16,700
Square footage | ft²				46,083
Subsequent event | Medical office building | Seattle, WA | Total real estate acquisitions
Business Acquisition [Line Items]
Purchase price		$ 11,000
Square footage | ft²		21,309