Summary of Activity Related to Other Intangible Assets Net (Detail) (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012 Non-Compete Agreements & Reacquired Franchise Rights		Sep. 30, 2012 Certificates of Need and Licenses	Sep. 30, 2012 Acquired Names of Business		Dec. 31, 2011 Acquired Names of Business
Goodwill and Other Assets Disclosure [Line Items]
Beginning Balance	$ 50,067,000	$ 4,200,000	[1]	$ 34,000,000	$ 11,800,000	[2]	$ 11,800,000	[2]
Additions	4,000,000	400,000	[1]	3,600,000
Amortization	(2,100,000)	(2,100,000)	[1]
Ending Balance	$ 51,959,000	$ 2,500,000	[1]	$ 37,600,000	$ 11,800,000	[2]	$ 11,800,000	[2]

[1] The weighted-average amortization period of our non-compete agreements and reacquired franchise rights is 1.4 and 0.8 years, respectively.

[2] Acquired Names of Business includes $11.7 million of unamortized acquired names and $0.1 million of amortized acquired names which have a weighted-average amortization period of 1.4 years.