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, 2017	$ 5,051,436		$ 66	$ 869	$ 7	$ 0	$ (371,814)	$ 5,353,209	$ 7,177	$ 4,989,514	$ 61,922
Balance at Dec. 31, 2017		$ 6,702
Common Stock
Issued/(converted)	7,860			5				7,855		7,860
Repurchased	(261,256)			(22)				(261,234)		(261,256)
Restricted share-based compensation expense	3,120							3,120		3,120
Dividends paid	(28,086)						(28,086)			(28,086)
Stock option expense	46,706							46,706		46,706
Distributions to noncontrolling interests	(7,742)	(500)									(7,742)
Purchase of noncontrolling interest	8,762	1									8,762
Comprehensive income:
Net income to UHS / noncontrolling interests	634,073							621,630		621,630	12,443
Net income attributable to redeemable noncontrolling interest		138
Foreign currency translation adjustments, net of income tax	(263)								(263)	(263)
Other, net of income tax	(15,480)								(15,480)	(15,480)
Subtotal - comprehensive income	618,330							621,630	(15,743)	605,887	12,443
Subtotal attributable to redeemable noncontrolling interest		138
Balance at Sep. 30, 2018	5,439,130		66	852	7	0	(399,900)	5,771,286	(8,566)	5,363,745	75,385
Balance at Sep. 30, 2018		6,341
Balance at Jun. 30, 2018	5,390,210		66	861	7	0	(390,618)	5,702,043	5,224	5,317,583	72,627
Balance at Jun. 30, 2018		6,341
Common Stock
Issued/(converted)	2,735			1				2,734		2,735
Repurchased	(120,869)			(10)				(120,859)		(120,869)
Restricted share-based compensation expense	1,420							1,420		1,420
Dividends paid	(9,282)						(9,282)			(9,282)
Stock option expense	14,202							14,202		14,202
Distributions to noncontrolling interests	(327)										(327)
Comprehensive income:
Net income to UHS / noncontrolling interests	174,831							171,746		171,746	3,085
Foreign currency translation adjustments, net of income tax	2,894								2,894	2,894
Other, net of income tax	(16,684)								(16,684)	(16,684)
Subtotal - comprehensive income	161,041							171,746	(13,790)	157,956	3,085
Balance at Sep. 30, 2018	5,439,130		66	852	7	0	(399,900)	5,771,286	(8,566)	5,363,745	75,385
Balance at Sep. 30, 2018		6,341
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 losses 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	4,000	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	$ 4,000	$ 4,061