Cumulative Amount of Unrecognized Hedge Losses Recorded in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	$ 31.9	$ 36.5
Net Investment Hedging [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	31.2	34.8
Net Investment Hedging [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	22.3	22.3
Net Investment Hedging [Member] | Long-Term Debt [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	8.9	12.5
Cash Flow Hedging [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	0.7	1.7
Cash Flow Hedging [Member] | Treasury Rate Lock [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	(1.0)	(1.1)
Cash Flow Hedging [Member] | Cross-Currency Swap [Member]
Derivative [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	$ 1.7	$ 2.8