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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Basic and Diluted:
Net income attributable to UHS	$ 141,245	$ 151,865	$ 532,694	$ 528,201
Less: Net income attributable to unvested restricted share grants	(81)	(69)	(257)	(242)
Net income attributable to UHS – basic and diluted	$ 141,164	$ 151,796	$ 532,437	$ 527,959
Weighted average number of common shares - basic	95,246	97,118	96,026	97,278
Net effect of dilutive stock options and grants based on the treasury stock method	731	1,203	771	1,257
Weighted average number of common shares and equivalents - diluted	95,977	98,321	96,797	98,535
Earnings per basic share attributable to UHS:	$ 1.48	$ 1.56	$ 5.54	$ 5.43
Earnings per diluted share attributable to UHS:	$ 1.47	$ 1.54	$ 5.50	$ 5.36