Acquisitions and Joint Ventures - Additional Information (Detail) $ in Thousands				12 Months Ended
	Sep. 01, 2017 Agency	Jun. 01, 2017 Agency	Jan. 01, 2017 Agency	Dec. 31, 2017 USD ($) Agency	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Intangible Assets, Net (Excluding Goodwill)				$ 134,610	$ 102,006
Goodwill Current Year Acquisition				392,601	307,317	$ 290,694
Total purchase price for acquisitions					24,100
Cash paid for acquisitions				$ 64,598	23,156	70,572
Minimum [Member]
Business Acquisition [Line Items]
Noncompete agreement estimated useful life				1 year
Maximum [Member]
Business Acquisition [Line Items]
Noncompete agreement estimated useful life				3 years
Community-Based Services [Member]
Business Acquisition [Line Items]
Intangible Assets, Net (Excluding Goodwill)				$ 9,500
Number of entities acquired | Agency	1
Home Health Reporting Unit [Member]
Business Acquisition [Line Items]
Number of entities acquired | Agency	7	3	28	5
Goodwill Current Year Acquisition				$ 261,456	210,839	202,995
Community Based Reporting Unit [Member]
Business Acquisition [Line Items]
Goodwill Current Year Acquisition				$ 28,541	18,820	17,972
Hospice Reporting Unit [Member]
Business Acquisition [Line Items]
Number of entities acquired | Agency	5	6	12	2
Goodwill Current Year Acquisition				$ 88,814	64,234	$ 58,136
Inpatient Hospice [Member]
Business Acquisition [Line Items]
Number of entities acquired | Agency	1	1	1
LTACH Agency [Member]
Business Acquisition [Line Items]
Number of entities acquired | Agency	6
Pharmacy [Member]
Business Acquisition [Line Items]
Number of entities acquired | Agency				1
2017 Acquisitions [Member]
Business Acquisition [Line Items]
Total purchase price for acquisitions				$ 80,200	10,400
Cash paid for acquisitions				$ 64,600
2016 Acquisitions [Member]
Business Acquisition [Line Items]
Cash paid for acquisitions					$ 23,100