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, 2018	$ 5,465,793		$ 66	$ 841	$ 7	$ 0	$ (409,156)	$ 5,793,262	$ 4,242	$ 5,389,262	$ 76,531
Balance at Dec. 31, 2018		$ 4,292
Common Stock
Issued/(converted)	8,383			10				8,373		8,383
Repurchased	(571,399)			(44)				(571,355)		(571,399)
Restricted share-based compensation expense	5,950							5,950		5,950
Dividends paid	(35,556)						(35,556)			(35,556)
Stock option expense	45,338							45,338		45,338
Distributions to noncontrolling interests	(11,555)	(500)									(11,555)
Purchase of noncontrolling interest	168										168
Comprehensive income:
Net income to UHS / noncontrolling interests	579,264							569,678		569,678	9,586
Net income attributable to redeemable noncontrolling interest		269
Foreign currency translation adjustments, net of income tax	(19,444)								(19,444)	(19,444)
Unrealized derivative gains on cash flow hedges, net of income tax	(2,997)								(2,997)	(2,997)
Subtotal - comprehensive income	556,823							569,678	(22,441)	547,237	9,586
Subtotal attributable to redeemable noncontrolling interest		269
Balance at Sep. 30, 2019	5,463,945		66	807	7	0	(444,712)	5,851,246	(18,199)	5,389,215	74,730
Balance at Sep. 30, 2019		4,061
Balance at Jun. 30, 2019	5,464,451		66	810	7	0	(427,109)	5,827,251	(7,936)	5,393,089	71,362
Balance at Jun. 30, 2019		3,986
Common Stock
Issued/(converted)	2,978			4				2,974		2,978
Repurchased	(93,327)			(7)				(93,320)		(93,327)
Restricted share-based compensation expense	2,291							2,291		2,291
Dividends paid	(17,603)						(17,603)			(17,603)
Stock option expense	14,860							14,860		14,860
Distributions to noncontrolling interests	(405)										(405)
Purchase of noncontrolling interest	168										168
Comprehensive income:
Net income to UHS / noncontrolling interests	100,795							97,190		97,190	3,605
Net income attributable to redeemable noncontrolling interest		75
Foreign currency translation adjustments, net of income tax	(10,263)								(10,263)	(10,263)
Subtotal - comprehensive income	90,532							97,190	(10,263)	86,927	3,605
Subtotal attributable to redeemable noncontrolling interest		75
Balance at Sep. 30, 2019	5,463,945		66	807	7	0	(444,712)	5,851,246	(18,199)	5,389,215	74,730
Balance at Sep. 30, 2019		4,061
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)	9,729			3				9,726		9,729
Repurchased	(200,098)			(20)				(200,078)		(200,098)
Restricted share-based compensation expense	6,958							6,958		6,958
Dividends paid	(17,344)						(17,344)			(17,344)
Stock option expense	41,565							41,565		41,565
Distributions to noncontrolling interests	(14,675)	(500)									(14,675)
Purchase of noncontrolling interest	(547)										(547)
Other	3,300										3,300
Comprehensive income:
Net income to UHS / noncontrolling interests	644,711							635,245		635,245	9,466
Net income attributable to redeemable noncontrolling interest		344
Foreign currency translation adjustments, net of income tax	(17,372)								(17,372)	(17,372)
Subtotal - comprehensive income	627,339							635,245	(17,372)	617,873	9,466
Subtotal attributable to redeemable noncontrolling interest		344
Balance at Sep. 30, 2020	6,035,098		66	777	7	0	(479,503)	6,426,920	14,521	5,962,788	72,310
Balance at Sep. 30, 2020	4,000	4,177
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
Common Stock
Issued/(converted)	3,766							3,766		3,766
Repurchased	(44)							(44)		(44)
Restricted share-based compensation expense	2,209							2,209		2,209
Stock option expense	12,988							12,988		12,988
Distributions to noncontrolling interests	(6,290)										(6,290)
Purchase of noncontrolling interest	(547)										(547)
Other	3,300										3,300
Comprehensive income:
Net income to UHS / noncontrolling interests	244,201							241,279		241,279	2,922
Net income attributable to redeemable noncontrolling interest		(110)
Foreign currency translation adjustments, net of income tax	13,943								13,943	13,943
Subtotal - comprehensive income	258,144							241,279	13,943	255,222	2,922
Subtotal attributable to redeemable noncontrolling interest		(110)
Balance at Sep. 30, 2020	6,035,098		$ 66	$ 777	$ 7	$ 0	$ (479,503)	$ 6,426,920	$ 14,521	$ 5,962,788	$ 72,310
Balance at Sep. 30, 2020	$ 4,000	$ 4,177