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
Mar. 31, 2017	Mar. 31, 2016
Basic and Diluted:
Net income attributable to UHS	$ 206,055	$ 190,759
Less: Net income attributable to unvested restricted share grants	(94)	(89)
Net income attributable to UHS – basic and diluted	$ 205,961	$ 190,670
Weighted average number of common shares - basic	96,585	97,607
Net effect of dilutive stock options and grants based on the treasury stock method	787	1,288
Weighted average number of common shares and equivalents - diluted	97,372	98,895
Earnings per basic share attributable to UHS:	$ 2.13	$ 1.95
Earnings per diluted share attributable to UHS:	$ 2.12	$ 1.93

Net income allocated to unvested restricted shares.

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Net income (loss) available to common stockholders, basic and diluted.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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