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, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Basic and diluted:
Net Income	$ 248,010	$ 100,870	$ 241,265	$ 237,398	$ 163,622	$ 174,881	$ 230,711	$ 228,669	$ 827,543	$ 797,883	$ 771,312
Less: Net income attributable to noncontrolling interest	$ (2,834)	$ (3,680)	$ (2,945)	$ (3,230)	$ (5,547)	$ (3,135)	$ (4,659)	$ (4,837)	(12,689)	(18,178)	(19,009)
Less: Net income attributable to unvested restricted share grants									(2,028)	(1,091)	(362)
Net income attributable to UHS—basic and diluted									$ 812,826	$ 778,614	$ 751,941
Basic earnings per share attributable to UHS:
Weighted average number of common shares—basic									88,762	93,276	95,652
Total basic earnings per share	$ 2.81	$ 1.10	$ 2.67	$ 2.57	$ 1.71	$ 1.85	$ 2.40	$ 2.37	$ 9.16	$ 8.35	$ 7.86
Diluted earnings per share attributable to UHS:
Weighted average number of common shares—basic									88,762	93,276	95,652
Net effect of dilutive stock options and grants based on the treasury stock method									278	474	673
Weighted average number of common shares and equivalents—diluted									89,040	93,750	96,325
Total diluted earnings per share	$ 2.79	$ 1.10	$ 2.66	$ 2.57	$ 1.70	$ 1.84	$ 2.39	$ 2.36	$ 9.13	$ 8.31	$ 7.81