Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) D Number_of_Visits	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Episode of care as episodic-based revenue, days | D			60
Percentage of total reimbursement of outlier payment			10.00%
Low utilization payment adjustment, maximum number of visits | Number_of_Visits			5
First threshold of therapy services required, visits | Number_of_Visits			6
Second threshold of services required, visits | Number_of_Visits			14
Third threshold of therapy services required, visits | Number_of_Visits			20
Historical collection rate from Medicare			99.00%
Episodes in progress that begin during reporting period, days | D			60
Hospice Medicare revenue rate accounted for routine care	98.00%	99.00%	98.00%	99.00%
Percentage of patient receivables outstanding			10.00%
Minimum days for accounts receivable outstanding to be fully reserved | D			365
Portion of accounts receivable derived from Medicare	60.00%				61.00%
Revenue adjustment to Medicare revenue	$ 3,500	$ 1,600	$ 11,900	$ 5,900
Rate of request for anticipated payment submitted for the initial episode of care			60.00%
Rate of request for anticipated payment submitted for subsequent episodes of care			50.00%
Maximum days to submit final bill from the start of episode | D			120
Maximum days to submit final bill from the date the request for anticipated payment was paid | D			60
Stockholders Equity Including Portion Attributable To Noncontrolling Interest	513,219		$ 513,219		$ 461,142
Tax benefit from stock options exercised and restricted stock vesting			0	$ 7,241
Accounting Standards Update 2016-09 [Member] | Net Income [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Share-based compensation, tax expense recognized	100
Tax benefit from stock options exercised and restricted stock vesting			3,000
Accounting Standards Update 2016-09 [Member] | Retained Earnings [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Stockholders Equity Including Portion Attributable To Noncontrolling Interest	400		$ 400
Home Health [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Historical collection rate from Medicare			99.00%
Hospice [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Historical collection rate from Medicare			99.00%
Cap Year Two Thousand Thirteen Through Two Thousand Sixteen [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Estimated amounts due back to Medicare					$ 800
Cap Year Two Thousand Thirteen Through Two Thousand Seventeen [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Estimated amounts due back to Medicare	$ 1,000		$ 1,000