Relationship with Universal Health Realty Income Trust and Related Party Transactions - Additional Information (Detail)	3 Months Ended			12 Months Ended
	Mar. 31, 2019 USD ($) Hospital Facility	Mar. 31, 2018 USD ($) Hospital	Dec. 31, 2013	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Net revenues	$ 2,804,391,000	$ 2,687,516,000
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
Chief Executive Officer | Scenario Forecast
Related Party Transaction [Line Items]
Payments to acquire life insurance policies, net				$ 1,100,000
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%
Percentage of annual incentive fee	20.00%
Percentage of advisory fee on average invested real estate assets	0.70%	0.70%			0.70%	0.70%	0.70%
Pre-tax share of income from the Trust	$ 300,000	$ 284,000
Dividends received from the Trust	531,000	524,000
Carrying value of investment in Trust	7,300,000				$ 7,500,000
Market value of investment in Trust	$ 59,600,000				48,300,000
Lease renewal period, years	5 years
Rent expense under operating leases	$ 4,000,000	$ 4,000,000
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
Number of free-standing emergency departments to be acquired | Facility	2
Relationship with Universal Health Realty Income Trust | Minimum
Related Party Transaction [Line Items]
Lease initial terms	13 years
Relationship with Universal Health Realty Income Trust | Minimum | Limited Liability Companies
Related Party Transaction [Line Items]
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
Relationship with Universal Health Realty Income Trust | Maximum | Limited Liability Companies
Related Party Transaction [Line Items]
Non-controlling ownership interests by subsidiaries	100.00%
Relationship with Universal Health Realty Income Trust | Advisory Fee
Related Party Transaction [Line Items]
Net revenues	$ 1,000,000	$ 904,000
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	51,000,000				$ 56,000,000
Premier, Inc. | Other (Income) Expense, Net | ASU 2016-01
Related Party Transaction [Line Items]
Unrealized loss	$ (4,000,000)