Acquisitions and Joint Ventures - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017 Agency	Jun. 30, 2017 Agency	Sep. 30, 2017 USD ($) Agency	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Business Combination, Consideration Transferred | $			$ 76,700
Payments to Acquire Businesses, Gross | $			$ 61,247	$ 20,332	$ 10,400
LifePoint
Business Acquisition [Line Items]
Number of home health agencies acquired			28
Number of hospice agencies acquired			12
Number of in-patient hospice unit agencies acquired			1
Baptist
Business Acquisition [Line Items]
Number of home health agencies acquired		3
Number of hospice agencies acquired		6
Christus
Business Acquisition [Line Items]
Number of home health agencies acquired	7
Number of hospice agencies acquired	5
Number of in-patient hospice unit agencies acquired	1
Community-Based Service Agencies Acquired	1
Number of Long-Term Acute Care Hospitals Acquired	6
Other acquisitions
Business Acquisition [Line Items]
Number of home health agencies acquired			2
Number of hospice agencies acquired			2
Number of in-patient hospice unit agencies acquired			1
Number of pharmacies acquired			1