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