Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic and diluted:
Net Income	$ 163,622	$ 174,881	$ 230,711	$ 228,669	$ 225,035	$ 145,362	$ 190,388	$ 210,527	$ 797,883	$ 771,312	$ 747,171
Less: Net income attributable to noncontrolling interest	$ (5,547)	$ (3,135)	$ (4,659)	$ (4,837)	$ (5,426)	$ (4,117)	$ (4,994)	$ (4,472)	(18,178)	(19,009)	(44,762)
Less: Net income attributable to unvested restricted share grants									(1,091)	(362)	(314)
Net income attributable to UHS—basic and diluted									$ 778,614	$ 751,941	$ 702,095
Basic earnings per share attributable to UHS:
Weighted average number of common shares—basic									93,276	95,652	97,208
Total basic earnings per share	$ 1.71	$ 1.85	$ 2.40	$ 2.37	$ 2.32	$ 1.48	$ 1.93	$ 2.13	$ 8.35	$ 7.86	$ 7.22
Diluted earnings per share attributable to UHS:
Weighted average number of common shares—basic									93,276	95,652	97,208
Net effect of dilutive stock options and grants based on the treasury stock method									474	673	1,172
Weighted average number of common shares and equivalents—diluted									93,750	96,325	98,380
Total diluted earnings per share	$ 1.70	$ 1.84	$ 2.39	$ 2.36	$ 2.31	$ 1.47	$ 1.91	$ 2.12	$ 8.31	$ 7.81	$ 7.14