Computation of Basic and Diluted Earnings per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Basic and diluted:
Net Income									$ 604,996	$ 554,023	$ 489,047
Less: Net income attributable to noncontrolling interest									(59,653)	(43,290)	(45,601)
Less: Net income attributable to unvested restricted share grants									(236)	(294)	(497)
Net income attributable to UHS-basic and diluted									$ 545,107	$ 510,439	$ 442,949
Weighted average number of common shares-basic									98,826	98,033	96,821
Total basic earnings per share	$ 1.75	$ 0.84	$ 1.53	$ 1.40	$ 1.27	$ 1.17	$ 1.55	$ 1.23	$ 5.52	$ 5.21	$ 4.57
Weighted average number of common shares									98,826	98,033	96,821
Net effect of dilutive stock options and grants based on the treasury stock method									1,718	1,328	890
Weighted average number of common shares and equivalents-diluted									100,544	99,361	97,711
Total diluted earnings per share	$ 1.71	$ 0.82	$ 1.51	$ 1.38	$ 1.24	$ 1.15	$ 1.53	$ 1.21	$ 5.42	$ 5.14	$ 4.53