Relationship with Universal Health Realty Income Trust and Other Related Party Transactions - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Related Party Transaction [Line Items]
Net revenues	$ 3,963,027,000	$ 3,562,774,000	$ 11,714,213,000	$ 10,578,430,000
Acute Care Hospital Services
Related Party Transaction [Line Items]
Net revenues	2,245,517,000	2,017,288,000	$ 6,604,007,000	5,993,899,000
Relationship with Universal Health Realty Income Trust
Related Party Transaction [Line Items]
Percentage of advisory fee on average invested real estate assets			0.70%		0.70%	0.70%	0.70%
Pre-tax share of income from the Trust	300,000	100,000	$ 914,000	670,000
Dividends received from the Trust	575,000	567,000	1,700,000	1,700,000
Carrying value of investment in Trust	6,200,000		6,200,000		$ 7,000,000
Market value of investment in Trust	$ 36,000,000.0		$ 36,000,000.0		$ 34,100,000
Relationship with Universal Health Realty Income Trust | Other Related Party Transactions
Related Party Transaction [Line Items]
Trust outstanding shares held, percentage	5.70%		5.70%
Relationship with Universal Health Realty Income Trust | Advisory Fee
Related Party Transaction [Line Items]
Net revenues	$ 1,400,000	$ 1,300,000	$ 4,100,000	$ 4,000,000