Summarized Financial Information of Equity Affiliates - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) Property	Dec. 31, 2014	Aug. 31, 2014 Property	Aug. 01, 2014 Property
Schedule Of Equity Method Investments [Line Items]
Percentage of minority ownership interests by parent		100.00%
Limited Liability Companies | Medical office buildings
Schedule Of Equity Method Investments [Line Items]
Number of real estate investments	5
Limited Liability Companies
Schedule Of Equity Method Investments [Line Items]
Number of real estate investments			8	6
Limited Liability Companies | Palmdale Medical Properties and Sparks Medical Properties
Schedule Of Equity Method Investments [Line Items]
Percentage of minority ownership interests by parent				100.00%
Minimum
Schedule Of Equity Method Investments [Line Items]
Percentage of minority ownership purchased from third-party members				5.00%
Number of days for Non-Offering Member either to purchase or sell its entire ownership interest to or from Offering Member	60 days
Maximum
Schedule Of Equity Method Investments [Line Items]
Percentage of minority ownership purchased from third-party members				15.00%
Number of days for Non-Offering Member either to purchase or sell its entire ownership interest to or from Offering Member	90 days
5 Unconsolidated Limited Liability Companies / Limited Partner | Minimum
Schedule Of Equity Method Investments [Line Items]
Non-controlling equity interest, ownership percentage	33.00%
5 Unconsolidated Limited Liability Companies / Limited Partner | Maximum
Schedule Of Equity Method Investments [Line Items]
Non-controlling equity interest, ownership percentage	95.00%
Arlington Medical Properties
Schedule Of Equity Method Investments [Line Items]
Non-controlling equity interest, ownership percentage	85.00%
Percentage of minority ownership purchased from third-party members	10.00%
Business acquisition additional consideration | $	$ 4.8