Derivative Instruments and Hedging Activities - Additional Information (Detail) € in Millions, £ in Millions, $ in Millions	Dec. 31, 2018 EUR (€)	Dec. 31, 2018 GBP (£)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 EUR (€)	Dec. 31, 2017 GBP (£)	Dec. 31, 2017 USD ($)	Aug. 10, 2017 EUR (€)
Sell [Member] | Contracts to Sell USD for GBP [Member]
Derivative [Line Items]
Notional amount | $			$ 310.3			$ 484.7
Sell [Member] | Contracts to Sell USD for EUR [Member]
Derivative [Line Items]
Notional amount | $			212.8			$ 465.2
Buy [Member] | Contracts to Sell USD for GBP [Member]
Derivative [Line Items]
Notional amount | £		£ 241.2			£ 362.3
Buy [Member] | Contracts to Sell USD for EUR [Member]
Derivative [Line Items]
Notional amount	€ 184.6			€ 390.0
Derivatives Designated as Accounting Hedges [Member] | Net Investment Hedging [Member] | 2015 Senior Notes [Member] | Cross-Currency Swap [Member]
Derivative [Line Items]
Notional amount	500.0
Derivatives Designated as Accounting Hedges [Member] | Net Investment Hedging [Member] | Currency Paid [Member] | Cross-Currency Swap [Member]
Derivative [Line Items]
Notional amount | $			830.0
Derivatives Designated as Accounting Hedges [Member] | Net Investment Hedging [Member] | Currency Received [Member] | Cross-Currency Swap [Member]
Derivative [Line Items]
Notional amount	€ 710.2
Derivatives Designated as Accounting Hedges [Member] | Cash Flow Hedging [Member] | 4.25% 2018 Notes, due 2029 [Member] | Treasury Rate Locks [Member]
Derivative [Line Items]
Notional amount | $			250.0
Derivatives Designated as Accounting Hedges [Member] | Cash Flow Hedging [Member] | Currency Paid [Member] | 2015 Senior Notes [Member] | Cross-Currency Swap [Member]
Derivative [Line Items]
Notional amount | $			$ 110.5
Derivative, swaption interest rate	3.945%	3.945%	3.945%
Derivatives Designated as Accounting Hedges [Member] | Cash Flow Hedging [Member] | Currency Received [Member] | 2015 Senior Notes [Member] | Cross-Currency Swap [Member]
Derivative [Line Items]
Notional amount	€ 100.0
Derivative, swaption interest rate	1.75%	1.75%	1.75%
Derivatives Designated as Accounting Hedges [Member] | 2021 [Member] | Currency Received [Member] | Cross-Currency Swap [Member]
Derivative [Line Items]
Notional amount	€ 422.5
Derivatives Designated as Accounting Hedges [Member] | 2022 [Member] | Currency Received [Member] | Cross-Currency Swap [Member]
Derivative [Line Items]
Notional amount	287.7
Bureau van Dijk (BvD) [Member] | Currency Paid [Member] | Sell [Member] | Contracts to Sell USD for GBP [Member]
Derivative [Line Items]
Notional amount | $			$ 41.0
Bureau van Dijk (BvD) [Member] | Currency Paid [Member] | Sell [Member] | Contracts to Sell USD for EUR [Member]
Derivative [Line Items]
Notional amount | $			$ 2,800.0
Bureau van Dijk (BvD) [Member] | Currency Received [Member] | Buy [Member] | Contracts to Sell USD for GBP [Member]
Derivative [Line Items]
Notional amount | £		£ 31.0
Bureau van Dijk (BvD) [Member] | Currency Received [Member] | Buy [Member] | Contracts to Sell USD for EUR [Member]
Derivative [Line Items]
Notional amount	€ 2,400.0
Bureau van Dijk (BvD) [Member] | Currency Received [Member] | Call Option [Member] | Foreign Exchange Option [Member]
Derivative [Line Items]
Notional amount							€ 2,700.0
Bureau van Dijk (BvD) [Member] | Currency Received [Member] | Put Option [Member] | Foreign Exchange Option [Member]
Derivative [Line Items]
Notional amount							€ 2,700.0