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)	5,405			6				5,399		5,405
Repurchased	(478,072)			(37)				(478,035)		(478,072)
Restricted share-based compensation expense	3,659							3,659		3,659
Dividends paid	(17,953)						(17,953)			(17,953)
Stock option expense	30,478							30,478		30,478
Distributions to noncontrolling interests	(11,150)	(500)									(11,150)
Comprehensive income:
Net income to UHS / noncontrolling interests	478,469							472,488		472,488	5,981
Net income attributable to redeemable noncontrolling interest		194
Foreign currency translation adjustments, net of income tax	(9,181)								(9,181)	(9,181)
Unrealized derivative gains on cash flow hedges, net of income tax	(2,997)								(2,997)	(2,997)
Subtotal - comprehensive income	466,291							472,488	(12,178)	460,310	5,981
Subtotal attributable to redeemable noncontrolling interest		194
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
Balance at Mar. 31, 2019	5,552,311		66	837	7	0	(418,237)	5,910,213	(10,471)	5,482,415	69,896
Balance at Mar. 31, 2019		3,843
Common Stock
Issued/(converted)	2,679							2,679		2,679
Repurchased	(340,843)			(27)				(340,816)		(340,843)
Restricted share-based compensation expense	2,136							2,136		2,136
Dividends paid	(8,872)						(8,872)			(8,872)
Stock option expense	14,719							14,719		14,719
Distributions to noncontrolling interests	(1,336)										(1,336)
Comprehensive income:
Net income to UHS / noncontrolling interests	241,122							238,320		238,320	2,802
Net income attributable to redeemable noncontrolling interest		143
Foreign currency translation adjustments, net of income tax	3,308								3,308	3,308
Unrealized derivative gains on cash flow hedges, net of income tax	(773)								(773)	(773)
Subtotal - comprehensive income	243,657							238,320	2,535	240,855	2,802
Subtotal attributable to redeemable noncontrolling interest		143
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
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	4,000	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	$ 4,000	$ 4,287