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)	3,112			2				3,110		3,112
Repurchased	(199,292)			(20)				(199,272)		(199,292)
Restricted share-based compensation expense	2,355							2,355		2,355
Dividends paid	(17,344)						(17,344)			(17,344)
Stock option expense	15,329							15,329		15,329
Distributions to noncontrolling interests	(5,234)	(500)									(5,234)
Comprehensive income:
Net income to UHS / noncontrolling interests	144,339							142,037		142,037	2,302
Net income attributable to redeemable noncontrolling interest		120
Foreign currency translation adjustments, net of income tax	(37,093)								(37,093)	(37,093)
Subtotal - comprehensive income	107,246							142,037	(37,093)	104,944	2,302
Subtotal attributable to redeemable noncontrolling interest		120
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
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)	3,360			4				3,356		3,360
Repurchased	(7,464)			(1)				(7,463)		(7,464)
Restricted share-based compensation expense	2,862							2,862		2,862
Dividends paid	(17,018)						(17,018)			(17,018)
Stock option expense	14,765							14,765		14,765
Distributions to noncontrolling interests	(4,525)										(4,525)
Purchase of ownership interests by minority members	7,603										7,603
Comprehensive income:
Net income to UHS / noncontrolling interests	209,169							209,091		209,091	78
Net income attributable to redeemable noncontrolling interest		(99)
Foreign currency translation adjustments, net of income tax	(8,880)								(8,880)	(8,880)
Subtotal - comprehensive income	200,289							209,091	(8,880)	200,211	78
Subtotal attributable to redeemable noncontrolling interest		(99)
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	$ 4,000	$ 4,470