Relationship with Universal Health Realty Income Trust and Related Party Transactions - Additional Information (Detail)	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2018 USD ($) Hospital Facility	Jun. 30, 2017 USD ($) Hospital	Dec. 31, 2013	Jun. 30, 2018 USD ($) Hospital Facility	Jun. 30, 2017 USD ($) Hospital	Dec. 31, 2017 USD ($)
Related Party Transaction [Line Items]
Net revenues	$ 2,681,353,000	$ 2,612,356,000		$ 5,368,869,000	$ 5,225,214,000
Chief Executive Officer
Related Party Transaction [Line Items]
Estimated payments to acquire life insurance policies				28,000,000
Payments to acquire life insurance policies, net				1,100,000	1,200,000
Chief Executive Officer | Trust Owned by CEO
Related Party Transaction [Line Items]
Estimated payments to acquire life insurance policies				$ 9,000,000
McAllen Medical Center
Related Party Transaction [Line Items]
Lease renewal option, exercised	5 years
End of lease term	2026-12			2026-12
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%			5.70%
Pre-tax share of income from the Trust	$ 590,000	236,000		$ 874,000	2,100,000
Carrying value of investment in Trust	8,600,000			8,600,000		$ 8,200,000
Market value of investment in Trust	50,400,000			$ 50,400,000		59,200,000
Lease renewal period, years				5 years
Rent expense under operating leases	$ 4,000,000	$ 4,000,000		$ 8,000,000	$ 8,000,000
Notice period on renewal of lease				90 days
Period of rights of refusal to leased facilities				180 days
Number of hospital facilities | Hospital	3	3		3	3
Number of free-standing emergency departments to be acquired | Facility	2			2
Relationship with Universal Health Realty Income Trust | Minimum
Related Party Transaction [Line Items]
Lease initial terms	13 years			13 years
Non-controlling ownership interests by subsidiaries	95.00%			95.00%
Relationship with Universal Health Realty Income Trust | Maximum
Related Party Transaction [Line Items]
Lease initial terms	15 years			15 years
Non-controlling ownership interests by subsidiaries	100.00%			100.00%
Relationship with Universal Health Realty Income Trust | Advisory Fee
Related Party Transaction [Line Items]
Net revenues	$ 900,000	$ 900,000		$ 1,900,000	$ 1,700,000
Premier, Inc. | Group Purchasing Organization Agreement | Restricted Stock
Related Party Transaction [Line Items]
Shares vesting period			7 years
Shares vesting period start year			2014
Shares vesting period end year			2020
Market value of retained vested shares				41,000,000		$ 33,000,000
Premier, Inc. | Other (Income) Expense, Net | ASU 2016-01
Related Party Transaction [Line Items]
Unrealized gain				$ 8,000,000