Significant Accounting Policies - Percentage of Net Service Revenue Earned by Category of Payor (Detail)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Significant Accounting Policies [Line Items]
Percentage of net service revenue	100.00%	100.00%
Home Health Medicare
Significant Accounting Policies [Line Items]
Percentage of net service revenue	71.20%	73.60%
Home Health Medicaid
Significant Accounting Policies [Line Items]
Percentage of net service revenue	0.90%	1.00%
Home Health Other Payor
Significant Accounting Policies [Line Items]
Percentage of net service revenue	27.90%	25.40%
Hospice Medicare
Significant Accounting Policies [Line Items]
Percentage of net service revenue	92.30%	94.10%
Hospice Medicaid
Significant Accounting Policies [Line Items]
Percentage of net service revenue	0.60%	0.30%
Hospice Other Payor
Significant Accounting Policies [Line Items]
Percentage of net service revenue	7.10%	5.60%
Community Based Services Medicaid
Significant Accounting Policies [Line Items]
Percentage of net service revenue	17.30%	16.50%
Community Based Services Other Payor
Significant Accounting Policies [Line Items]
Percentage of net service revenue	82.70%	83.50%
Medicare revenue
Significant Accounting Policies [Line Items]
Percentage of net service revenue	64.00%	63.90%
Medicaid revenue
Significant Accounting Policies [Line Items]
Percentage of net service revenue	0.00%
Managed Care, commercial, and other revenue
Significant Accounting Policies [Line Items]
Percentage of net service revenue	36.00%	36.10%