Quarterly Results (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net revenues	$ 2,642,787	$ 2,541,864	$ 2,612,356	$ 2,612,858	$ 2,475,685	$ 2,409,872	$ 2,430,855	$ 2,449,798	$ 10,409,865	$ 9,766,210	$ 9,043,451
Net income	225,035	145,362	190,388	210,527	178,738	157,265	195,449	215,719	771,312	747,171	750,698
Less: Net income attributable to noncontrolling interests	5,426	4,117	4,994	4,472	4,530	5,400	9,872	24,960	19,009	44,762	70,170
Net income attributable to UHS	$ 219,609	$ 141,245	$ 185,394	$ 206,055	$ 174,208	$ 151,865	$ 185,577	$ 190,759	$ 752,303	$ 702,409	$ 680,528
Total basic earnings per share	$ 2.32	$ 1.48	$ 1.93	$ 2.13	$ 1.80	$ 1.56	$ 1.91	$ 1.95	$ 7.86	$ 7.22	$ 6.89
Total diluted earnings per share	$ 2.31	$ 1.47	$ 1.91	$ 2.12	$ 1.78	$ 1.54	$ 1.89	$ 1.93	$ 7.81	$ 7.14	$ 6.76