Schedule of Weighted Average Remaining Contractual Life for Options Outstanding and Weighted Average Exercise Price Per Share for Exercisable Options (Parenthetical) (Detail)	12 Months Ended
Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Weighted average forfeiture rate	13.06%

Share based compensation arrangement by share based payment award options forfeitures in period weighted average forfeiture rate.

No definition available.

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Namespace Prefix:	uhs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration