Acquisitions - Allocation of Purchase Price (Detail) (USD $)
Mar. 31, 2015
Dec. 31, 2014
Business Acquisition [Line Items]    
Goodwill $ 1,449,822,000 $ 1,451,887,000
Alifabs Group [Member]    
Business Acquisition [Line Items]    
Cash and cash equivalents 2,100,000  
Other current assets 15,700,000  
Identifiable intangible assets 26,900,000  
Goodwill 15,300,000  
Other noncurrent assets 600,000  
Less: Liabilities assumed (11,800,000)  
Net acquisition cost $ 48,800,000