Computation of Basic and Diluted Earnings Per Share for classes A, B, C and D Common Stockholders (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Basic and Diluted:
Net income attributable to UHS	$ 226,052	$ 185,394	$ 449,884	$ 391,449
Less: Net income attributable to unvested restricted share grants	(392)	(82)	(496)	(176)
Net income attributable to UHS – basic and diluted	$ 225,660	$ 185,312	$ 449,388	$ 391,273
Weighted average number of common shares - basic	93,842	96,247	94,034	96,416
Net effect of dilutive stock options and grants based on the treasury stock method	439	795	448	791
Weighted average number of common shares and equivalents - diluted	94,281	97,042	94,482	97,207
Earnings per basic share attributable to UHS:	$ 2.40	$ 1.93	$ 4.78	$ 4.06
Earnings per diluted share attributable to UHS:	$ 2.39	$ 1.91	$ 4.76	$ 4.03