XML 60 R46.htm IDEA: XBRL DOCUMENT v3.8.0.1
Acquisitions - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Business Acquisition [Line Items]      
Goodwill $ 713,811,000 $ 414,936,000  
Goodwill, expected tax deductible amount 0    
Acquisition-related expenses 17,300,000 1,200,000 $ 9,800,000
Byram Healthcare      
Business Acquisition [Line Items]      
Combined consideration, net of cash acquired 367,000,000    
Goodwill 288,691,000    
Domestic      
Business Acquisition [Line Items]      
Goodwill 468,697,000 $ 180,006,000  
Domestic | Byram Healthcare      
Business Acquisition [Line Items]      
Goodwill $ 289,000,000    
Minimum      
Business Acquisition [Line Items]      
Acquired intangible assets , useful life 3 years    
Maximum      
Business Acquisition [Line Items]      
Acquired intangible assets , useful life 10 years