Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Redeemable Noncontrolling Interest	Class A	Class B	Class C	Class D	Cumulative Dividends	Retained Earnings	Retained Earnings Cumulative Effect Period of Adoption Adjustment	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect Period of Adoption Adjustment	UHS Common Stockholders' Equity	Noncontrolling Interest
Balance at Dec. 31, 2017	$ 5,051,436		$ 66	$ 869	$ 7	$ 0	$ (371,814)	$ 5,353,209	$ (3,353)	$ 7,177	$ 3,353	$ 4,989,514	$ 61,922
Balance at Dec. 31, 2017		$ 6,702
Common Stock
Issued/(converted) including tax benefits from exercise of stock options	11,888			6				11,882				11,888
Repurchased	(414,002)			(34)				(413,968)				(414,002)
Restricted share-based compensation expense	2,924							2,924				2,924
Dividends paid	(37,342)						(37,342)					(37,342)
Stock option expense	61,061							61,061				61,061
Distributions to noncontrolling interests	(12,095)	(2,500)											(12,095)
Other	8,616												8,616
Comprehensive income:
Net income to UHS / noncontrolling interests	797,793							779,705				779,705	18,088
Net income attributable to redeemable noncontrolling interest		90
Reclassification due to adoption of ASU 2018-02								1,802		(1,802)
Foreign currency translation adjustments (net of income tax effect)	2,894									2,894		2,894
Unrealized derivative gains on cash flow hedges (net of income tax effect)	(2,138)									(2,138)		(2,138)
Minimum pension liability (net of income tax effect)	(5,242)									(5,242)		(5,242)
Subtotal - comprehensive income	793,307							778,154		(2,935)		775,219	18,088
Subtotal attributable to redeemable noncontrolling interest		90
Balance at Dec. 31, 2018	5,465,793		66	841	7		(409,156)	5,793,262		4,242		5,389,262	76,531
Balance at Dec. 31, 2018		4,292
Common Stock
Issued/(converted) including tax benefits from exercise of stock options	10,940			10				10,930				10,940
Repurchased	(753,927)			(57)				(753,870)				(753,927)
Restricted share-based compensation expense	8,222							8,222				8,222
Dividends paid	(53,003)						(53,003)					(53,003)
Stock option expense	60,106							60,106				60,106
Distributions to noncontrolling interests	(15,359)	(500)											(15,359)
Other	1,446												1,446
Comprehensive income:
Net income to UHS / noncontrolling interests	827,002							814,854				814,854	12,148
Net income attributable to redeemable noncontrolling interest		541
Foreign currency translation adjustments (net of income tax effect)	24,193									24,193		24,193
Unrealized derivative gains on cash flow hedges (net of income tax effect)	(2,997)									(2,997)		(2,997)
Minimum pension liability (net of income tax effect)	6,455									6,455		6,455
Subtotal - comprehensive income	854,653							814,854		27,651		842,505	12,148
Subtotal attributable to redeemable noncontrolling interest		541
Balance at Dec. 31, 2019	5,578,871		66	794	7		(462,159)	5,933,504		31,893		5,504,105	74,766
Balance at Dec. 31, 2019		4,333
Common Stock
Issued/(converted) including tax benefits from exercise of stock options	12,758			4				12,754				12,758
Repurchased	(206,719)			(20)				(206,699)				(206,719)
Restricted share-based compensation expense	9,505							9,505				9,505
Dividends paid	(17,344)						(17,344)					(17,344)
Stock option expense	54,661							54,661				54,661
Distributions to noncontrolling interests	(19,305)	(500)											(19,305)
Purchase of Ownership Interests by Minority Members	17,959												17,959
Other	3,300												3,300
Comprehensive income:
Net income to UHS / noncontrolling interests	952,054							943,953				943,953	8,101
Net income attributable to redeemable noncontrolling interest		736
Foreign currency translation adjustments (net of income tax effect)	12,870									12,870		12,870
Minimum pension liability (net of income tax effect)	3,357									3,357		3,357
Subtotal - comprehensive income	968,281							943,953		16,227		960,180	8,101
Subtotal attributable to redeemable noncontrolling interest		736
Balance at Dec. 31, 2020	6,401,967		$ 66	$ 778	$ 7		$ (479,503)	$ 6,747,678		$ 48,120		$ 6,317,146	$ 84,821
Balance at Dec. 31, 2020	$ 5,000	$ 4,569