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, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Basic and Diluted:
Net income attributable to UHS	$ 171,746	$ 141,245	$ 621,630	$ 532,694
Less: Net income attributable to unvested restricted share grants	(317)	(81)	(813)	(257)
Net income attributable to UHS – basic and diluted	$ 171,429	$ 141,164	$ 620,817	$ 532,437
Weighted average number of common shares - basic	92,849	95,246	93,639	96,026
Net effect of dilutive stock options and grants based on the treasury stock method	481	731	459	771
Weighted average number of common shares and equivalents - diluted	93,330	95,977	94,098	96,797
Earnings per basic share attributable to UHS:	$ 1.85	$ 1.48	$ 6.63	$ 5.54
Earnings per diluted share attributable to UHS:	$ 1.84	$ 1.47	$ 6.60	$ 5.50