Derivative Financial Instruments - Summary of Outstanding Foreign Exchange Derivatives Designated as Net Investment Hedges of Foreign Currency Risk (Detail) - Designated as Hedging Instrument [Member] - Net Investment Hedges [Member] € in Thousands, £ in Thousands, kr in Thousands, $ in Thousands, $ in Thousands	Sep. 30, 2021 CAD ($) DerivativeInstrument	Sep. 30, 2021 SEK (kr) DerivativeInstrument	Sep. 30, 2021 EUR (€) DerivativeInstrument	Sep. 30, 2021 GBP (£) DerivativeInstrument	Sep. 30, 2021 AUD ($) DerivativeInstrument	Dec. 31, 2020 CAD ($) DerivativeInstrument	Dec. 31, 2020 EUR (€) DerivativeInstrument	Dec. 31, 2020 GBP (£) DerivativeInstrument	Dec. 31, 2020 AUD ($) DerivativeInstrument
Buy USD / Sell SEK Forward [Member] | SEK [Member]
Derivative [Line Items]
Number of Instruments	1	1	1	1	1
Notional Amount | kr		kr 999,500
Buy USD / Sell EUR Forward [Member] | EUR [Member]
Derivative [Line Items]
Number of Instruments	6	6	6	6	6	8	8	8	8
Notional Amount | €			€ 817,642				€ 754,722
Buy USD / Sell GBP Forward [Member] | GBP [Member]
Derivative [Line Items]
Number of Instruments	1	1	1	1	1	4	4	4	4
Notional Amount | £				£ 542,551				£ 372,487
Buy USD / Sell AUD Forward [Member] | AUD [Member]
Derivative [Line Items]
Number of Instruments	1	1	1	1	1	1	1	1	1
Notional Amount | $					$ 89,500				$ 92,800
Buy USD / Sell CAD Forward [Member] | CAD [Member]
Derivative [Line Items]
Number of Instruments	1	1	1	1	1	1	1	1	1
Notional Amount | $	$ 21,000					$ 26,200