Relationship with Universal Health Realty Income Trust and Related Party Transactions - Additional Information (Detail)	3 Months Ended				6 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($) Bed Lease SquareFoot	Jun. 30, 2019 USD ($) Facility	Jun. 30, 2018 USD ($)	Dec. 31, 2013	Jun. 30, 2019 USD ($) Hospital Facility	Jun. 30, 2018 USD ($) Hospital	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Net revenues		$ 2,855,168,000	$ 2,681,353,000		$ 5,659,559,000	$ 5,368,869,000
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 | Trust Owned by CEO
Related Party Transaction [Line Items]
Estimated payments to acquire life insurance policies					$ 9,000,000
Scenario Forecast | Chief Executive Officer
Related Party Transaction [Line Items]
Payments to acquire life insurance policies, net							$ 1,100,000
Scenario Forecast | Joint Venture Agreement
Related Party Transaction [Line Items]
Lease initial terms	20 years
Lease renewal period, years	10 years
Number of beds | Bed	108
Number of triple net lease | Lease	5
Number of square foot to be constructed | SquareFoot	80,000
Expected aggregate fee	$ 750,000
Estimated project cost	37,500,000
Estimated initial annual rent	$ 2,700,000
Expected project to begin and be completed year	2020
Minimum
Related Party Transaction [Line Items]
Lease initial terms		5 years			5 years
Minimum | Chief Executive Officer
Related Party Transaction [Line Items]
Estimated death benefit proceeds					$ 37,000,000
Maximum
Related Party Transaction [Line Items]
Lease initial terms		10 years			10 years
Relationship with Universal Health Realty Income Trust
Related Party Transaction [Line Items]
Trust outstanding shares held, percentage		5.70%			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		$ 200,000	590,000		$ 500,000	$ 874,000
Dividends received from the Trust		536,000	528,000		1,100,000	1,100,000
Carrying value of investment in Trust		6,900,000			6,900,000			$ 7,500,000
Market value of investment in Trust		66,900,000			$ 66,900,000			48,300,000
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
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
Relationship with Universal Health Realty Income Trust | Minimum | Limited Liability Companies
Related Party Transaction [Line Items]
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
Relationship with Universal Health Realty Income Trust | Maximum | Limited Liability Companies
Related Party Transaction [Line Items]
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		$ 1,000,000.0	$ 900,000		$ 2,000,000.0	$ 1,900,000
Premier, Inc. | Other (Income) Expense, Net | ASU 2016-01
Related Party Transaction [Line Items]
Unrealized gain					2,000,000
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					$ 58,000,000			$ 56,000,000