New Construction, Acquisitions and Dispositions - Additional Information (Detail)	1 Months Ended			9 Months Ended
	Sep. 30, 2019 USD ($) Time	Jul. 31, 2019 USD ($) Time	Jun. 30, 2018 USD ($) Time	Sep. 30, 2019 USD ($) Time Acquisition Disposition	Sep. 30, 2018 Disposition
Business Acquisitions And Dispositions [Line Items]
Number of acquisitions | Acquisition				0
Number of dispositions | Disposition				0	0
Beaumont Medical Sleep Center Building
Business Acquisitions And Dispositions [Line Items]
Number of term renewal options | Time			2
Additional renewal terms			5 years
Total purchase price			$ 4,000,000.0
Percentage of building area leased			100.00%
Initial lease terms			9 years 6 months
Universal Health Services, Inc
Business Acquisitions And Dispositions [Line Items]
Master flex lease term	10 years
Percentage of rentable square feet	50.00%
Percentage of third-party lease rentable square feet threshold for reduction execution	50.00%
Number of term renewal options | Time	6			6
Additional renewal terms				5 years
Universal Health Services, Inc | Medical office buildings
Business Acquisitions And Dispositions [Line Items]
Ground lease agreement period	75 years
Number of term renewal options | Time	2			2
Additional renewal terms	10 years
Universal Health Services, Inc | Maximum
Business Acquisitions And Dispositions [Line Items]
Initial lease terms				15 years
Universal Health Services, Inc | Minimum
Business Acquisitions And Dispositions [Line Items]
Initial lease terms				13 years
Universal Health Services, Inc and Catholic Health Initiatives
Business Acquisitions And Dispositions [Line Items]
Number of term renewal options | Time		5
Triple net lease agreement period		20 years
Renewal option term		10 years
Project manager's aggregate fee		$ 750,000
Estimated approximate project cost		37,500,000
Estimated initial annual rent		$ 2,700,000
Des Moines Medical Properties, LLC
Business Acquisitions And Dispositions [Line Items]
Land and development and construction costs	$ 3,600,000			$ 3,600,000
Grayson Properties II LP | Medical office buildings
Business Acquisitions And Dispositions [Line Items]
Committed investment in equity or member loans	700,000			700,000
Grayson Properties II LP | Maximum | Medical office buildings
Business Acquisitions And Dispositions [Line Items]
Commitment to investment	$ 17,900,000			$ 17,900,000
Grayson Properties II LP | Denison, Texas
Business Acquisitions And Dispositions [Line Items]
Non-controlling equity interest, ownership percentage	95.00%			95.00%