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)	2,666			2				2,664		2,666
Repurchased	(9,441)			(1)				(9,440)		(9,441)
Restricted share-based compensation expense	545							545		545
Dividends paid	(9,422)						(9,422)			(9,422)
Stock option expense	18,879							18,879		18,879
Distributions to noncontrolling interests	(3,717)	(500)									(3,717)
Purchase of noncontrolling interest	7,213										7,213
Comprehensive income:
Net income to UHS / noncontrolling interests	228,790							223,832		223,832	4,958
Net income attributable to redeemable noncontrolling interest		(121)
Foreign currency translation adjustments, net of income tax	(4,341)								(4,341)	(4,341)
Other, net of income tax	1,795								1,795	1,795
Unrealized derivative losses on cash flow hedges, net of income tax	1,619								1,619	1,619
Subtotal - comprehensive income	227,863							223,832	(927)	222,905	4,958
Subtotal attributable to redeemable noncontrolling interest		(121)
Balance at Mar. 31, 2018	5,286,022		66	870	7		(381,236)	5,589,689	6,250	5,215,646	70,376
Balance at Mar. 31, 2018		6,081
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)	2,726			6				2,720		2,726
Repurchased	(137,229)			(10)				(137,219)		(137,229)
Restricted share-based compensation expense	1,523							1,523		1,523
Dividends paid	(9,081)						(9,081)			(9,081)
Stock option expense	15,759							15,759		15,759
Distributions to noncontrolling interests	(9,814)	(500)									(9,814)
Comprehensive income:
Net income to UHS / noncontrolling interests	237,347							234,168		234,168	3,179
Net income attributable to redeemable noncontrolling interest		51
Foreign currency translation adjustments, net of income tax	(12,489)								(12,489)	(12,489)
Unrealized derivative losses on cash flow hedges, net of income tax	(2,224)								(2,224)	(2,224)
Subtotal - comprehensive income	222,634							234,168	(14,713)	219,455	3,179
Subtotal attributable to redeemable noncontrolling interest		51
Balance at Mar. 31, 2019	5,552,311		$ 66	$ 837	$ 7		$ (418,237)	$ 5,910,213	$ (10,471)	$ 5,482,415	$ 69,896
Balance at Mar. 31, 2019	$ 4,000	$ 3,843