Cumulative Amount of Unrecognized Hedge Losses Recorded in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	$ 5.7	$ 36.5
Net Investment Hedging [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	4.6	34.8
Net Investment Hedging [Member] | FX forwards [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	23.5	22.3
Net Investment Hedging [Member] | Long Term Debt [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	(18.9)	12.5
Cash Flow Hedging [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	1.1	1.7
Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	(0.4)	(1.1)
Cash Flow Hedging [Member] | Cross-Currency Swap [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	$ 1.5	$ 2.8