Summary of Activity Related to Other Intangible Assets, Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill and Intangible Assets [Line Items]
Beginning balance	$ 44,047	$ 33,200	$ 36,700
Additions	5,200	11,100
Write-off		(300)	(200)
Other intangibles impairment charge			(3,100)
Amortization	(2,500)		(200)
Ending balance	46,755	44,047	33,200
Noncompete Agreements [Member]
Goodwill and Intangible Assets [Line Items]
Beginning balance	5,900	0	200
Additions	1,500	5,900
Write-off		0	0
Other intangibles impairment charge			0
Amortization	(2,500)		(200)
Ending balance	4,900	5,900	0
Certificates Of Need And Licenses [Member]
Goodwill and Intangible Assets [Line Items]
Beginning balance	23,900	23,100	25,400
Additions	200	1,100
Write-off		(300)	(200)
Other intangibles impairment charge			(2,100)
Amortization	0		0
Ending balance	24,100	23,900	23,100
Acquired Names Of Business [Member]
Goodwill and Intangible Assets [Line Items]
Beginning balance	14,200	10,100	11,100
Additions	3,500	4,100
Write-off		0	0
Other intangibles impairment charge			(1,000)
Amortization	0		0
Ending balance	$ 17,700	$ 14,200	$ 10,100