Real Estate Investments - Acquisitions (Details) $ in Thousands								6 Months Ended
	Jun. 26, 2019 USD ($) ft²	Jun. 14, 2019 USD ($) ft²	Jun. 11, 2019 USD ($) ft²	Jun. 10, 2019 USD ($) ft²	Apr. 02, 2019 USD ($) ft²	Mar. 28, 2019 USD ($) ft²	May 03, 2018 property	Jun. 30, 2019 USD ($) ft²
Business Acquisition [Line Items]
Financing lease liabilities								$ 14,216
Real Estate Acquisition
Business Acquisition [Line Items]
Purchase price								195,200
Cash consideration								192,700
Real Estate								196,800
Other								$ (4,100)
Square footage | ft²								595,203
Medical Office Building | Washington, D.C. (4) | Real Estate Acquisition
Business Acquisition [Line Items]
Number of properties acquired | property							2
Date Acquired						Mar. 28, 2019
Purchase price						$ 46,000
Cash consideration						45,900
Real Estate						50,200
Other						$ (4,300)
Square footage | ft²						158,338
Financing lease liabilities								$ 14,300
Above-market lease intangibles								$ 5,200
Medical Office Building | Indianapolis, IN (5) | Real Estate Acquisition
Business Acquisition [Line Items]
Date Acquired						Mar. 28, 2019
Purchase price						$ 47,000
Cash consideration						44,800
Real Estate						43,700
Other						$ 1,100
Square footage | ft²						143,499
Prepaid ground leases						$ 800
Below-market lease intangible						$ 900
Medical Office Building | Atlanta, GA | Real Estate Acquisition
Business Acquisition [Line Items]
Date Acquired					Apr. 02, 2019
Purchase price					$ 28,000
Cash consideration					28,000
Real Estate					28,000
Other					$ 0
Square footage | ft²					47,963
Medical Office Building | Dallas, TX | Real Estate Acquisition
Business Acquisition [Line Items]
Date Acquired				Jun. 10, 2019
Purchase price				$ 17,000
Cash consideration				16,700
Real Estate				17,000
Other				$ (300)
Square footage | ft²				89,990
Medical Office Building | Seattle WA | Real Estate Acquisition
Business Acquisition [Line Items]
Date Acquired	Jun. 28, 2019	Jun. 14, 2019	Jun. 11, 2019
Purchase price	$ 30,500	$ 19,000	$ 7,700
Cash consideration	30,400	19,100	7,800
Real Estate	30,600	19,500	7,800
Other	$ (200)	$ (400)	$ 0
Square footage | ft²	78,288	47,255	29,870