Relationship with UHS and Related Party Transactions - Additional Information (Detail)	1 Months Ended	2 Months Ended	3 Months Ended	12 Months Ended			60 Months Ended
	Apr. 30, 2017 Time	Feb. 28, 2015 ft² Property Time	Mar. 31, 2015 USD ($) ft² Property	Dec. 31, 2017 USD ($) Property Time	Dec. 31, 2016 USD ($) Option	Dec. 31, 2015 USD ($)	Dec. 31, 2017 USD ($) Property Time
Related Party Transaction [Line Items]
Annual advisory fee as percentage of average invested real estate assets				0.70%	0.70%	0.70%	0.70%
Advisory fee				$ 3,577,000	$ 3,263,000	$ 2,810,000
Wholly Owned Subsidiaries Of U H S Real Property Of Two Newly Constructed And Recently Opened F E Ds Located In Weslaco And Mission Texas
Related Party Transaction [Line Items]
Number of term renewal options | Time		6
Additional renewal terms		5 years	5 years
Number of real properties purchased | Property		2	2
Lease agreement period		10 years	10 years
Wholly Owned Subsidiaries Of U H S Real Property Of Two Newly Constructed And Recently Opened F E Ds Located In Weslaco And Mission Texas | Recently Opened Free Standing Emergency Departments | Weslaco
Related Party Transaction [Line Items]
Area of acquired building | ft²		13,600	13,600
Wholly Owned Subsidiaries Of U H S Real Property Of Two Newly Constructed And Recently Opened F E Ds Located In Weslaco And Mission Texas | Recently Opened Free Standing Emergency Departments | Mission
Related Party Transaction [Line Items]
Area of acquired building | ft²		13,600	13,600
Mission and Weslaco Freestanding Emergency Departments
Related Party Transaction [Line Items]
Estimated acquisition cost of free-standing emergency departments			$ 12,800,000
Estimated rental revenues			$ 900,000
Mission and Weslaco Freestanding Emergency Departments | First four renewal options
Related Party Transaction [Line Items]
Percentage increase in annual lease rate			2.00%
Minimum | Mission and Weslaco Freestanding Emergency Departments | First four renewal options
Related Party Transaction [Line Items]
Additional renewal terms, covering year			2025
Minimum | Mission and Weslaco Freestanding Emergency Departments | Last two renewal options
Related Party Transaction [Line Items]
Additional renewal terms, covering year			2045
Minimum | 5 Unconsolidated Limited Liability Companies
Related Party Transaction [Line Items]
Non-controlling equity interest, ownership percentage				33.00%			33.00%
Maximum
Related Party Transaction [Line Items]
Number of term renewal options | Option					5
Maximum | Mission and Weslaco Freestanding Emergency Departments | First four renewal options
Related Party Transaction [Line Items]
Additional renewal terms, covering year			2044
Maximum | Mission and Weslaco Freestanding Emergency Departments | Last two renewal options
Related Party Transaction [Line Items]
Additional renewal terms, covering year			2054
Maximum | 5 Unconsolidated Limited Liability Companies
Related Party Transaction [Line Items]
Non-controlling equity interest, ownership percentage				95.00%			95.00%
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
Percentage ownership of outstanding shares				5.70%	5.80%		5.70%
Universal Health Services, Inc | Henderson Medical Plaza
Related Party Transaction [Line Items]
Number of term renewal options | Time	2
Additional renewal terms	10 years
Ground lease agreement period	75 years
Amount invested in MOB under construction				$ 12,400,000			$ 12,400,000
Universal Health Services, Inc | Customer Concentration Risk | Revenues
Related Party Transaction [Line Items]
Percentage of revenues generated from leases				22.00%	24.00%	25.00%	25.00%
Universal Health Services, Inc | Customer Concentration Risk | Combined consolidated and unconsolidated revenue
Related Party Transaction [Line Items]
Percentage of revenues generated from leases				19.00%	19.00%	20.00%	20.00%
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
Universal Health Services, Inc | Maximum
Related Party Transaction [Line Items]
Initial lease terms				15 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%			20.00%
Incentive fees				$ 0	$ 0	$ 0
Advisory fee				3,600,000	3,300,000	2,800,000
Average invested real estate assets				$ 511,000,000	$ 466,000,000	$ 401,000,000
Universal Health Services of Delaware Inc | Minimum
Related Party Transaction [Line Items]
Percentage of equity to be exceeded for incentive distribution				15.00%			15.00%