Cumulative Amount of Unrecognized Hedge Losses Recorded in Accumulated Other Comprehensive Income (Detail) (Net Investment Hedging [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Hedge Underlying Gain Loss [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	$ 39.8	$ 20.9
Foreign Exchange Contract [Member]
Hedge Underlying Gain Loss [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	32.0	20.9
Two thousand fifteen senior notes [Member]
Hedge Underlying Gain Loss [Line Items]
Cumulative amount of unrecognized hedge losses recorded in AOCI	$ 7.8	$ 0