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, 2014	$ 3,791,080		$ 66	$ 914	$ 7	$ 0	$ (255,196)	$ 4,015,387	$ (25,232)	$ 3,735,946	$ 55,134
Balance at Dec. 31, 2014		$ 239,552
Common Stock
Issued/(converted) including tax benefits from exercise of stock options	56,487			14				56,473		56,487
Repurchased	(224,260)			(18)				(224,242)		(224,260)
Restricted share-based compensation expense	393							393		393
Dividends paid	(39,532)						(39,532)			(39,532)
Stock option expense	37,982							37,982		37,982
Distributions to noncontrolling interests	(11,114)	(51,106)									(11,114)
Other	(613)										(613)
Comprehensive income:
Net income to UHS / noncontrolling interests	696,635							680,528		680,528	16,107
Net income attributable to redeemable noncontrolling interest		54,063
Foreign currency translation adjustments	(1,728)								(1,728)	(1,728)
Amortization of terminated hedge (net of income tax effect)	(216)								(216)	(216)
Unrealized derivative gains on cash flow hedges (net of income tax effect)	2,687								2,687	2,687
Minimum pension liability (net of income tax effect)	1,360								1,360	1,360
Subtotal	698,738							680,528	2,103	682,631	16,107
Subtotal attributable to redeemable noncontrolling interest		54,063
Balance at Dec. 31, 2015	4,309,161		66	910	7		(294,728)	4,566,521	(23,129)	4,249,647	59,514
Balance at Dec. 31, 2015		242,509
Common Stock
Issued/(converted) including tax benefits from exercise of stock options	54,853			13				54,840		54,853
Repurchased	(346,890)			(30)				(346,860)		(346,890)
Restricted share-based compensation expense	1,439							1,439		1,439
Dividends paid	(38,875)						(38,875)			(38,875)
Stock option expense	45,777							45,777		45,777
Distributions to noncontrolling interests	(17,735)	(51,847)									(17,735)
Acquisition of noncontrolling interests in majority owned businesses	(132,852)	(206,200)						(132,852)		(132,852)
Other	2,690										2,690
Comprehensive income:
Net income to UHS / noncontrolling interests	722,314							702,409		702,409	19,905
Net income attributable to redeemable noncontrolling interest		24,857
Foreign currency translation adjustments	(10,038)								(10,038)	(10,038)
Amortization of terminated hedge (net of income tax effect)	(107)								(107)	(107)
Unrealized loss on marketable security (net of income tax effect)	(1,398)								(1,398)	(1,398)
Unrealized derivative gains on cash flow hedges (net of income tax effect)	902								902	902
Minimum pension liability (net of income tax effect)	8,353								8,353	8,353
Subtotal	720,026							702,409	(2,288)	700,121	19,905
Subtotal attributable to redeemable noncontrolling interest		24,857
Balance at Dec. 31, 2016	4,597,594		66	893	7		(333,603)	4,891,274	(25,417)	4,533,220	64,374
Balance at Dec. 31, 2016		9,319
Common Stock
Issued/(converted) including tax benefits from exercise of stock options	10,379			9				10,370		10,379
Repurchased	(356,413)			(33)				(356,380)		(356,413)
Restricted share-based compensation expense	1,377							1,377		1,377
Dividends paid	(38,211)						(38,211)			(38,211)
Stock option expense	54,265							54,265		54,265
Distributions to noncontrolling interests	(22,932)	(1,781)									(22,932)
Other	635										635
Comprehensive income:
Net income to UHS / noncontrolling interests	772,148							752,303		752,303	19,845
Net income attributable to redeemable noncontrolling interest		(836)
Foreign currency translation adjustments	26,678								26,678	26,678
Unrealized loss on marketable security (net of income tax effect)	(1,360)								(1,360)	(1,360)
Unrealized derivative gains on cash flow hedges (net of income tax effect)	4,189								4,189	4,189
Minimum pension liability (net of income tax effect)	3,087								3,087	3,087
Subtotal	804,742							752,303	32,594	784,897	19,845
Subtotal attributable to redeemable noncontrolling interest		(836)
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	$ 7,000	$ 6,702