Stock-Based Compensation (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Unearned non-cash stock-based compensation
Weighted average period for recognition of stock-based compensation expense	2 years 4 months 24 days
Unearned non-cash stock-based compensation expense expected to be recognized	$ 3,400,000
Estimated forfeiture rate (as a percent)	2.00%
Options | UHS Holdco, Inc., (Parent)
Number of Options
Outstanding at the beginning of the period (in shares)	36,668
Granted (in shares)	0
Forfeited or expired (in shares)	(3,562)
Outstanding at the end of the period (in shares)	33,106	36,668
Exercisable at the end of the period (in shares)	26,479
Remaining authorized options not yet issued (in shares)	10,581
Weighted average exercise price
Outstanding at the beginning of the period (in dollars per share)	$ 1.12
Forfeited or expired (in dollars per share)	$ 1.04
Outstanding at the end of the period (in dollars per share)	$ 1.13	$ 1.12
Exercisable at the end of the period (in dollars per share)	$ 1.05
Aggregate intrinsic value
Outstanding	9,957,000	11,253,000
Exercisable	$ 9,748,000
Weighted average remaining contractual term
Outstanding	5 years 6 months	5 years 7 months 6 days
Exercisable	4 years 7 months 6 days