Acquisitions and Divestitures - Additional Information (Detail)		3 Months Ended										12 Months Ended
	Dec. 28, 2016 USD ($) Facility	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 Facility	Sep. 30, 2016 Bed	Dec. 31, 2018 USD ($) Facility Bed	Dec. 31, 2017 USD ($) Bed	Dec. 31, 2016 USD ($) $ / shares
Business Acquisition [Line Items]
Goodwill recognition description												Goodwill of the facilities acquired during each of the last 3 years is computed, pursuant to the residual method, by deducting the fair value of the acquired assets and liabilities from the total purchase price. The factors that contribute to the recognition of goodwill, which may also influence the purchase price, include the following for each of the acquired facilities: (i) the historical cash flows and income levels; (ii) the reputations in their respective markets; (iii) the nature of the respective operations, and; (iv) the future cash flows and income growth projections.
Aggregate cash proceeds from divestiture of businesses													$ 0	$ 0
Net revenues		$ 2,754,496,000	$ 2,648,913,000	$ 2,681,353,000	$ 2,687,516,000	$ 2,642,787,000	$ 2,541,864,000	$ 2,612,356,000	$ 2,612,858,000			$ 10,772,278,000	$ 10,409,865,000	9,766,210,000
The Limes
Business Acquisition [Line Items]
Number of beds | Bed													18
Net revenues from discontinued operations													$ 3,000,000
Income before income taxes from discontinued operations													953,000
After-tax income from discontinued operations													770,000
2018 Acquisitions of Assets and Businesses
Business Acquisition [Line Items]
Acquisition, cash paid												$ 110,000,000
Danshell Group [Member] | Located in U.K.
Business Acquisition [Line Items]
Number of behavioral health care facilities | Facility												25
Gulfport Behavioral Health System | Located in Gulfport
Business Acquisition [Line Items]
Number of beds | Bed												109
2017 Acquisitions of Assets and Businesses
Business Acquisition [Line Items]
Acquisition, cash paid													$ 23,000,000
2016 Acquisitions of Assets and Businesses
Business Acquisition [Line Items]
Acquisition, cash paid														614,000,000
Unaudited pro forma net revenues														9,980,000,000
Unaudited pro forma net income attributable to UHS														$ 730,000,000
Unaudited pro forma net income attributable to UHS per diluted share | $ / shares														$ 7.25
Cambian Adult Services
Business Acquisition [Line Items]
Total purchase price of acquisition	$ 473,000,000
Cambian Adult Services | Located in U.K.
Business Acquisition [Line Items]
Number of behavioral health care facilities | Facility	79									79
Number of outpatient centers | Facility	2									2
Desert View Hospital
Business Acquisition [Line Items]
Net revenues														$ 12,000,000
Desert View Hospital | Located in Pahrump, Nevada
Business Acquisition [Line Items]
Number of beds | Bed											25