Relationship with Universal Health Services, Inc. ("UHS") and Related Party Transactions - Additional Information (Detail)		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2019 USD ($) Property Time Lease	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) Property Time Lease	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Related Party Transaction [Line Items]
Remaining lease terms on ground leases		58 years 7 months 6 days		58 years 7 months 6 days
Aggregate lease payments for 2019	[1]	$ 120,000		$ 120,000
Aggregate lease payments for 2020		480,000		480,000		$ 474,000
Aggregate lease payments for 2021		480,000		480,000		474,000
Aggregate lease payments for 2022		480,000		480,000		474,000
Aggregate lease payments for 2023		480,000		480,000		474,000
Aggregate lease payments for thereafter		$ 25,921,000		$ 25,921,000		$ 25,582,000
Annual advisory fee as percentage of average invested real estate assets		0.70%	0.70%	0.70%	0.70%
Universal Health Services, Inc
Related Party Transaction [Line Items]
Number of term renewal options | Time		6		6
Additional renewal terms				5 years
Number of medical office buildings and free standing emergency departments | Property				17
Option to renew lease, notice period prior to termination date of current term				90 days
Period to purchase respective leased facilities at same price after lease terms				180 days
Renewal period of respective leased facilities at same price after lease terms				180 days
Number of renewal options at existing lease rates | Time				3
Number of ground leases | Lease		11		11
Aggregate lease payments for 2019		$ 479,000		$ 479,000
Aggregate lease payments for 2020		481,000		481,000
Aggregate lease payments for 2021		481,000		481,000
Aggregate lease payments for 2022		481,000		481,000
Aggregate lease payments for 2023		481,000		481,000
Aggregate lease payments for thereafter		$ 28,100,000		$ 28,100,000
Percentage ownership of outstanding shares		5.70%		5.70%		5.70%
Universal Health Services, Inc | Customer Concentration Risk | Revenues
Related Party Transaction [Line Items]
Percentage of revenues generated from leases and tenants		21.00%	21.00%	22.00%	21.00%
Universal Health Services, Inc | Customer Concentration Risk | Revenues | Tenants
Related Party Transaction [Line Items]
Percentage of revenues generated from leases and tenants		30.00%	30.00%	31.00%	30.00%
Universal Health Services, Inc | Hospital Facilities Leased
Related Party Transaction [Line Items]
Number of hospital facilities leased | Property		3		3
Universal Health Services, Inc | Minimum
Related Party Transaction [Line Items]
Initial lease terms				13 years
Remaining lease terms on ground leases		30 years		30 years
Universal Health Services, Inc | Maximum
Related Party Transaction [Line Items]
Initial lease terms				15 years
Remaining lease terms on ground leases		79 years		79 years
Universal Health Services of Delaware Inc
Related Party Transaction [Line Items]
Annual incentive fee to Advisor as percentage of cash available for distribution						20.00%
Incentive fees						$ 0
Advisory fee		$ 1,000,000.0	$ 975,000	$ 3,000,000.0	$ 2,800,000
Type of Cost, Good or Service [Extensible List]		us-gaap:ManagementServiceMember	us-gaap:ManagementServiceMember	us-gaap:ManagementServiceMember	us-gaap:ManagementServiceMember
Average invested real estate assets		$ 578,000,000	$ 557,000,000	$ 564,000,000	$ 538,000,000
Universal Health Services of Delaware Inc | Minimum
Related Party Transaction [Line Items]
Percentage of equity to be exceeded for incentive distribution						15.00%

[1] Represents the remaining three months of 2019.