XML 82 R69.htm IDEA: XBRL DOCUMENT v3.8.0.1
Goodwill and Intangibles, net - Additional Information (Detail) - USD ($)
$ in Millions
 3 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Finite-Lived Intangible Assets [Line Items]    
Indefinite-Lived Intangible Assets (Excluding Goodwill) $ 1,025.3 $ 1,024.3
Document Period End Date Dec. 31, 2017  
Finite-Lived Intangible Assets, Accumulated Amortization $ 336.4 $ 297.1
Finite-Lived Intangible Assets, Amortization Expense, Year Two 57.5  
VOBA    
Finite-Lived Intangible Assets [Line Items]    
Finite-Lived Intangible Assets, Amortization Expense, Year Two 57.4  
Finite-Lived Intangible Assets, Amortization Expense, Year Three 55.0  
Finite-Lived Intangible Assets, Amortization Expense, Year Four 49.7  
Finite-Lived Intangible Assets, Amortization Expense, Year Five $ 48.0