Derivative and Other Financial Instruments and Fair Value Measurements - Losses on Assets Recorded at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring Basis
Goodwill impairment		$ 33.6	$ 61.8	$ 33.6	$ 61.8	$ 0.0
Property, plant and equipment impairment	$ 40.5			40.5
RANA
Fair Value Assets And Liabilities Measured On Recurring Basis
Goodwill impairment				33.6	61.8
Fair Value, Measurements, Nonrecurring Basis | RANA
Fair Value Assets And Liabilities Measured On Recurring Basis
Goodwill impairment				33.6	61.8
Property, plant and equipment impairment				40.5
Identifiable intangible assets impairment				10.1
Fair Value, Measurements, Nonrecurring Basis | Cosmedicine
Fair Value Assets And Liabilities Measured On Recurring Basis
Identifiable intangible assets impairment					0.1
Inventories impairment				$ 0.1	$ 0.7