Significant Accounting Policies - Percentage of Net Service Revenue Earned by Category of Payor (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Significant Accounting Policies [Line Items]
Document Fiscal Year Focus			2018
Revenue By Payor	100.00%	100.00%	100.00%	100.00%
Home Health Medicare
Significant Accounting Policies [Line Items]
Revenue By Payor	72.90%	72.40%	72.30%	73.00%
Home Health Medicaid
Significant Accounting Policies [Line Items]
Revenue By Payor	1.50%	1.20%	1.30%	1.20%
Home Health Other Payor
Significant Accounting Policies [Line Items]
Revenue By Payor	25.60%	26.40%	26.40%	25.80%
Hospice Medicare
Significant Accounting Policies [Line Items]
Revenue By Payor	91.10%	92.90%	91.70%	93.50%
Hospice Medicaid
Significant Accounting Policies [Line Items]
Revenue By Payor	0.60%	0.90%	0.60%	0.60%
Hospice Other Payor
Significant Accounting Policies [Line Items]
Revenue By Payor	8.30%	6.20%	7.70%	5.90%
Community Based Services Medicaid
Significant Accounting Policies [Line Items]
Revenue By Payor	24.70%	18.00%	23.10%	17.30%
Community Based Services Other Payor
Significant Accounting Policies [Line Items]
Revenue By Payor	75.30%	82.00%	76.90%	82.70%
Facility-Based Medicare revenue
Significant Accounting Policies [Line Items]
Revenue By Payor	58.70%	65.00%	61.40%	64.40%
Facility-Based Medicaid revenue
Significant Accounting Policies [Line Items]
Revenue By Payor	0.00%	0.00%	0.00%	0.00%
Facility-Based Managed Care, commercial, and other revenue
Significant Accounting Policies [Line Items]
Revenue By Payor	41.30%	35.00%	38.60%	35.60%
Healthcare Innovations Medicare
Significant Accounting Policies [Line Items]
Revenue By Payor	26.70%	0.00%	26.70%	0.00%
Healthcare Innovations Medicaid
Significant Accounting Policies [Line Items]
Revenue By Payor	0.40%	0.00%	0.40%	0.00%
Healthcare Innovations Other Payor
Significant Accounting Policies [Line Items]
Revenue By Payor	72.90%	0.00%	72.90%	0.00%
HCI
Significant Accounting Policies [Line Items]
Revenue By Payor		0.00%		0.00%