Relationship with Universal Health Realty Income Trust and Other Related Party Transactions - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2015 USD ($) Facility	Dec. 31, 2013	Dec. 31, 2017 USD ($) Hospital Facility	Dec. 31, 2016 USD ($) Hospital	Dec. 31, 2015 USD ($) Hospital
Related Party Transaction [Line Items]
Number of hospital facilities | Hospital			3
Chief Executive Officer
Related Party Transaction [Line Items]
Estimated payments to acquire life insurance policies			$ 28,000,000
Payments to acquire life insurance policies			1,200,000	$ 1,300,000
Chief Executive Officer | Trust Owned by CEO
Related Party Transaction [Line Items]
Estimated payments to acquire life insurance policies			9,000,000
Minimum | Chief Executive Officer
Related Party Transaction [Line Items]
Estimated death benefit proceeds			$ 37,000,000
Relationship with Universal Health Realty Income Trust
Related Party Transaction [Line Items]
Trust outstanding shares held, percentage			5.70%
Advisory fee earned			$ 3,600,000	$ 3,300,000	$ 2,800,000
Percentage of advisory fee on average invested real estate assets			0.70%	0.70%	0.70%
Pre-tax share of income from the Trust			$ 2,600,000	$ 1,000,000	$ 1,400,000
Share of gain included in the share of trust			1,700,000		500,000
Dividends received from the Trust			2,100,000	2,000,000	2,000,000
Carrying value of investment in Trust			8,200,000	7,700,000
Market value of investment in Trust			$ 59,200,000	51,700,000
Lease renewal period, years			5 years
Rent expense under operating leases			$ 16,000,000	$ 15,900,000	$ 15,600,000
Number of hospital facilities | Hospital			3	3	3
Notice period on renewal of lease			90 days
Period of rights of refusal to leased facilities			180 days
Number of free-standing emergency departments to be acquired | Facility			2
Aggregate construction cost/sales proceeds	$ 13,000,000
Aggregate rent expense paid	$ 900,000
Relationship with Universal Health Realty Income Trust | Texas
Related Party Transaction [Line Items]
Lease initial terms	10 years
Number of free-standing emergency departments to be acquired | Facility	2
Renewal options term at existing lease rates	5 years
Renewal options term at fair market lease rates	5 years
Relationship with Universal Health Realty Income Trust | Minimum
Related Party Transaction [Line Items]
Lease initial terms			13 years
Non-controlling ownership interests by subsidiaries			95.00%
Relationship with Universal Health Realty Income Trust | Maximum
Related Party Transaction [Line Items]
Lease initial terms			15 years
Non-controlling ownership interests by subsidiaries			100.00%
Premier, Inc. | Group Purchasing Organization Agreement | Restricted Stock
Related Party Transaction [Line Items]
Market value of retained vested shares			$ 33,000,000	$ 23,000,000
Shares vesting period		7 years
Shares vesting period start year		2014
Shares vesting period end year		2020