Derivative Instruments and Hedging Activities - Additional Information (Detail) € in Millions, £ in Millions, $ in Millions	Dec. 31, 2017 EUR (€)	Dec. 31, 2017 GBP (£)	Dec. 31, 2017 USD ($)
Sell [Member] | Contracts to Sell USD for GBP [Member]
Derivative [Line Items]
Notional amount | $			$ 484.7
Sell [Member] | Contracts to Sell USD for EUR [Member]
Derivative [Line Items]
Notional amount | $			$ 465.2
Buy [Member] | Contracts to Sell USD for GBP [Member]
Derivative [Line Items]
Notional amount | £		£ 362.3
Buy [Member] | Contracts to Sell USD for EUR [Member]
Derivative [Line Items]
Notional amount	€ 390.0
Derivatives Designated as Accounting Hedges [Member] | Cross-Currency Swap [Member] | Currency Paid [Member] | 2015 Senior Notes [Member]
Derivative [Line Items]
Notional amount	€ 110.5
Derivative, swaption interest rate	3.945%	3.945%	3.945%
Derivatives Designated as Accounting Hedges [Member] | Cross-Currency Swap [Member] | Currency Received [Member] | 2015 Senior Notes [Member]
Derivative [Line Items]
Notional amount | $			$ 110.5
Derivative, swaption interest rate	1.75%	1.75%	1.75%
Derivatives Designated as Accounting Hedges [Member] | Net Investment Hedging [Member] | 2015 Senior Notes [Member]
Derivative [Line Items]
Notional amount	€ 500.0
Bureau van Dijk (BvD) [Member] | Foreign Exchange Option [Member] | Currency Received [Member] | Call Option [Member]
Derivative [Line Items]
Notional amount	2,700.0
Bureau van Dijk (BvD) [Member] | Foreign Exchange Option [Member] | Currency Received [Member] | Put Option [Member]
Derivative [Line Items]
Notional amount	2,700.0
Bureau van Dijk (BvD) [Member] | Derivatives Not Designated as Investment Hedges [Member] | Foreign Exchange Option [Member] | Sell [Member] | Contracts to Sell USD for GBP [Member]
Derivative [Line Items]
Notional amount | $			$ 41.0
Bureau van Dijk (BvD) [Member] | Derivatives Not Designated as Investment Hedges [Member] | Foreign Exchange Option [Member] | Sell [Member] | Contracts to Sell USD for EUR [Member]
Derivative [Line Items]
Notional amount | $			$ 2,800.0
Bureau van Dijk (BvD) [Member] | Derivatives Not Designated as Investment Hedges [Member] | Foreign Exchange Option [Member] | Buy [Member] | Contracts to Sell USD for GBP [Member]
Derivative [Line Items]
Notional amount | £		£ 31.0
Bureau van Dijk (BvD) [Member] | Derivatives Not Designated as Investment Hedges [Member] | Foreign Exchange Option [Member] | Buy [Member] | Contracts to Sell USD for EUR [Member]
Derivative [Line Items]
Notional amount	€ 2,400.0