Condensed 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	Accumulated Other Comprehensive Income (Loss)	UHS Common Stockholders' Equity	Noncontrolling Interest
Balance at Dec. 31, 2019	$ 5,578,871		$ 66	$ 794	$ 7	$ 0	$ (462,159)	$ 5,933,504	$ 31,893	$ 5,504,105	$ 74,766
Balance at Dec. 31, 2019		$ 4,333
Common Stock
Issued/(converted)	5,963			3				5,960		5,963
Repurchased	(200,054)			(20)				(200,034)		(200,054)
Restricted share-based compensation expense	4,749							4,749		4,749
Dividends paid	(17,344)						(17,344)			(17,344)
Stock option expense	28,577							28,577		28,577
Distributions to noncontrolling interests	(8,385)	(500)									(8,385)
Comprehensive income:
Net income to UHS / noncontrolling interests	400,510							393,966		393,966	6,544
Net income attributable to redeemable noncontrolling interest		454
Foreign currency translation adjustments, net of income tax	(31,315)								(31,315)	(31,315)
Subtotal - comprehensive income	369,195							393,966	(31,315)	362,651	6,544
Subtotal attributable to redeemable noncontrolling interest		454
Balance at Jun. 30, 2020	5,761,572		66	777	7	0	(479,503)	6,166,722	578	5,688,647	72,925
Balance at Jun. 30, 2020		4,287
Balance at Mar. 31, 2020	5,485,043		66	776	7	0	(479,503)	5,897,063	(5,200)	5,413,209	71,834
Balance at Mar. 31, 2020		3,953
Common Stock
Issued/(converted)	2,851			1				2,850		2,851
Repurchased	(762)							(762)		(762)
Restricted share-based compensation expense	2,394							2,394		2,394
Stock option expense	13,248							13,248		13,248
Distributions to noncontrolling interests	(3,151)										(3,151)
Comprehensive income:
Net income to UHS / noncontrolling interests	256,171							251,929		251,929	4,242
Net income attributable to redeemable noncontrolling interest		334
Foreign currency translation adjustments, net of income tax	5,778								5,778	5,778
Subtotal - comprehensive income	261,949							251,929	5,778	257,707	4,242
Subtotal attributable to redeemable noncontrolling interest		334
Balance at Jun. 30, 2020	5,761,572		66	777	7	0	(479,503)	6,166,722	578	5,688,647	72,925
Balance at Jun. 30, 2020		4,287
Balance at Dec. 31, 2020	6,401,967		66	778	7	0	(479,503)	6,747,678	48,120	6,317,146	84,821
Balance at Dec. 31, 2020		4,569
Common Stock
Issued/(converted)	6,444			5				6,439		6,444
Repurchased	(368,080)			(23)				(368,057)		(368,080)
Restricted share-based compensation expense	6,102							6,102		6,102
Dividends paid	(33,874)						(33,874)			(33,874)
Stock option expense	30,243							30,243		30,243
Distributions to noncontrolling interests	(5,414)	(203)									(5,414)
Purchase of ownership interests by minority members	12,669										12,669
Comprehensive income:
Net income to UHS / noncontrolling interests	534,019							534,115		534,115	(96)
Net income attributable to redeemable noncontrolling interest		327
Foreign currency translation adjustments, net of income tax	(11,996)								(11,996)	(11,996)
Subtotal - comprehensive income	522,023							534,115	(11,996)	522,119	(96)
Subtotal attributable to redeemable noncontrolling interest		327
Balance at Jun. 30, 2021	6,572,080		66	760	7	0	(513,377)	6,956,520	36,124	6,480,100	91,980
Balance at Jun. 30, 2021	5,000	4,693
Balance at Mar. 31, 2021	6,601,839		66	781	7	0	(496,521)	6,970,289	39,240	6,513,862	87,977
Balance at Mar. 31, 2021		4,470
Common Stock
Issued/(converted)	3,084			1				3,083		3,084
Repurchased	(360,616)			(22)				(360,594)		(360,616)
Restricted share-based compensation expense	3,240							3,240		3,240
Dividends paid	(16,856)						(16,856)			(16,856)
Stock option expense	15,478							15,478		15,478
Distributions to noncontrolling interests	(889)	(203)									(889)
Purchase of ownership interests by minority members	5,066										5,066
Comprehensive income:
Net income to UHS / noncontrolling interests	324,850							325,024		325,024	(174)
Net income attributable to redeemable noncontrolling interest		426
Foreign currency translation adjustments, net of income tax	(3,116)								(3,116)	(3,116)
Subtotal - comprehensive income	321,734							325,024	(3,116)	321,908	(174)
Subtotal attributable to redeemable noncontrolling interest		426
Balance at Jun. 30, 2021	6,572,080		$ 66	$ 760	$ 7	$ 0	$ (513,377)	$ 6,956,520	$ 36,124	$ 6,480,100	$ 91,980
Balance at Jun. 30, 2021	$ 5,000	$ 4,693