Acquisitions, Dispositions and New Construction - Additional Information (Detail)	1 Months Ended			3 Months Ended
	Nov. 30, 2016 USD ($)	Sep. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2017 USD ($) Acquisition	Mar. 31, 2016 USD ($)	Mar. 12, 2017
Business Acquisitions And Dispositions [Line Items]
Number of acquisitions | Acquisition				0
Cash received for property exchange transaction					$ 0
Henderson Medical Plaza | Universal Health Services, Inc
Business Acquisitions And Dispositions [Line Items]
Maximum amount of investment for development and construction			$ 21,100,000		$ 21,100,000
Amount invested in MOB under construction				$ 10,800,000
2704 North Tenaya Way
Business Acquisitions And Dispositions [Line Items]
Total purchase price	$ 15,300,000
Non-recourse third-party debt	$ 7,100,000
Frederick Crestwood Medical Office Building
Business Acquisitions And Dispositions [Line Items]
Total purchase price		$ 24,300,000
Madison Professional Office Building
Business Acquisitions And Dispositions [Line Items]
Total purchase price			$ 10,100,000
Madison Professional Office Building | Lease Agreements
Business Acquisitions And Dispositions [Line Items]
Renewal Term (years)			6 years 2 months 12 days
Medical office buildings
Business Acquisitions And Dispositions [Line Items]
Acquired intangible assets include in-place leases amortization period			6 years 2 months 12 days
St. Mary's Professional Office Building
Business Acquisitions And Dispositions [Line Items]
Entitled to aggregate of net cash proceeds from divestiture				57,300,000
Net sale proceeds due				11,300,000
Gain on divestiture of property				$ 27,200,000
Arlington Medical Properties
Business Acquisitions And Dispositions [Line Items]
Ownership prior to minority interest purchase				85.00%
Remaining percentage owned by third party member						15.00%
Total purchase price				$ 7,900,000
Repayment of loan				$ 21,400,000