Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) D Number_of_Visits	Dec. 31, 2014 USD ($)	Dec. 31, 2013 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			99.00%	98.00%	99.00%
Percentage of patient receivables outstanding			10.00%
Percentage of Patient Receivables Outstanding Over Ten Percent			10.50%
Minimum days for accounts receivable outstanding to be fully reserved | D			365
Portion of accounts receivable derived from Medicare			64.00%	69.00%
Revenue adjustment to Medicare revenue			$ 6,100	$ 5,100	$ 9,000
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
Asset Impairment Charges			$ 77,268	3,107	9,492
Income Taxes [Line Items]
Net deferred tax assets (liabilities)			125,200	122,400
Property Plant And Equipment [Line Items]
Internally developed computer software				75,800
Depreciation			20,000	28,000	35,200
Debt Issuance Costs [Line Items]
Amortization of deferred debt issuance costs/debt discount			959	797	699
Write-off of deferred debt issuance cost	$ 2,500
Deferred debt issuance cost	2,400
Unamortized debt issuance costs			$ 3,400	2,800
Unamortized debt issuance costs, weighted average amortization period, years			4 years 7 months
Non-cash compensation			$ 11,824	5,597	6,519
Share-based compensation, tax benefit recognized			4,700	2,000	2,500
Advertising expense			6,900	4,700	3,900
AMS3 Homecare and Hospice [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Asset Impairment Charges		$ 75,200
Corporate Headquarters [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Asset Impairment Charges	2,100
Home Health [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Asset Impairment Charges			0	1,600	8,500
Hospice [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Asset Impairment Charges			0	1,500	1,000
Credit Agreement [Member]
Debt Issuance Costs [Line Items]
Deferred debt issuance cost	2,400
Deferred Debt Issuance Costs [Member]
Debt Issuance Costs [Line Items]
Amortization of deferred debt issuance costs/debt discount			$ 800	700	$ 700
Write-off of deferred debt issuance cost	$ 1,000
Noncompete Agreements [Member]
Goodwill and Intangible Assets [Line Items]
Estimated Useful Life of Intangible Assets			3 years
Reacquired Franchise Rights And Acquired Names [Member]
Goodwill and Intangible Assets [Line Items]
Estimated Useful Life of Intangible Assets			5 years
Cap Year Two Thousand Thirteen Through Two Thousand Sixteen [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Estimated amounts due back to Medicare			$ 1,400
Cap Year Two Thousand Thirteen Through Two Thousand Fifteen [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Estimated amounts due back to Medicare				$ 2,800