XML 54 R40.htm IDEA: XBRL DOCUMENT v3.8.0.1
Financial Instruments - Derivative Instruments Used to Hedge against Balance Sheet Foreign Currency Exposures (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Foreign exchange gains (losses) related to balance sheet re-measurement $ 9.7 $ (5.6) $ (7.9)
Foreign Exchange Forward | Other income | Derivatives Not Designated as Hedging Instruments      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Recognized gains (losses) in interest and other income, net $ (9.2) $ 6.4 $ 7.0