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Financial Instruments and Fair Value Measurements - Additional Information (Detail) - USD ($)
$ in Millions
Sep. 30, 2017
Dec. 31, 2016
Derivative Instruments And Hedging Activities Disclosure [Abstract]    
Carrying amount of notes $ 347.3 $ 443.3
Level 3 [Member]    
Derivative Instruments And Hedging Activities Disclosure [Abstract]    
Approximate fair value of notes $ 348.7 $ 445.2