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)	5,125			4				5,121		5,125
Repurchased	(140,387)			(12)				(140,375)		(140,387)
Restricted share-based compensation expense	1,700							1,700		1,700
Dividends paid	(18,804)						(18,804)			(18,804)
Stock option expense	32,504							32,504		32,504
Distributions to noncontrolling interests	(7,415)	(500)									(7,415)
Purchase of noncontrolling interest	8,762	1									8,762
Comprehensive income:
Net income to UHS / noncontrolling interests	459,242							449,884		449,884	9,358
Net income attributable to redeemable noncontrolling interest		138
Foreign currency translation adjustments, net of income tax	(3,157)								(3,157)	(3,157)
Other, net of income tax	1,204								1,204	1,204
Subtotal - comprehensive income	457,289							449,884	(1,953)	447,931	9,358
Subtotal attributable to redeemable noncontrolling interest		138
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
Balance at Mar. 31, 2018	5,286,022		66	870	7	0	(381,236)	5,589,689	6,250	5,215,646	70,376
Balance at Mar. 31, 2018		6,081
Common Stock
Issued/(converted)	2,459			2				2,457		2,459
Repurchased	(130,946)			(11)				(130,935)		(130,946)
Restricted share-based compensation expense	1,155							1,155		1,155
Dividends paid	(9,382)						(9,382)			(9,382)
Stock option expense	13,625							13,625		13,625
Distributions to noncontrolling interests	(3,698)										(3,698)
Purchase of noncontrolling interest	1,549	1									1,549
Comprehensive income:
Net income to UHS / noncontrolling interests	230,452							226,052		226,052	4,400
Net income attributable to redeemable noncontrolling interest		259
Foreign currency translation adjustments, net of income tax	1,184								1,184	1,184
Other, net of income tax	(591)								(591)	(591)
Unrealized derivative losses on cash flow hedges, net of income tax	(1,619)								(1,619)	(1,619)
Subtotal - comprehensive income	229,426							226,052	(1,026)	225,026	4,400
Subtotal attributable to redeemable noncontrolling interest		259
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
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 losses 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	4,000	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 losses 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	$ 4,000	$ 3,986