Debt - Summary of Debt (Detail) - USD ($) $ in Thousands		Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Debt		$ 10,656,337	$ 8,934,187
Debt issue costs and discount, net		(75,314)	(68,729)
Debt, net		10,581,023	8,865,458
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt	[1]	245,227	165,407
Interim Credit Facility [Member]
Debt Instrument [Line Items]
Debt		650,000
Term Loan [Member]
Debt Instrument [Line Items]
Debt		200,000	200,000
Term Loan [Member] | United Kingdom [Member]
Debt Instrument [Line Items]
Debt	[2]	943,180	956,900
Term Loan [Member] | Australia [Member]
Debt Instrument [Line Items]
Debt	[2]	867,240	923,280
4.000% Senior Unsecured Notes Due 2022 [Member]
Debt Instrument [Line Items]
Debt	[2]	579,000	610,800
2.550% Senior Unsecured Notes due 2023 [Member]
Debt Instrument [Line Items]
Debt	[2]	538,960	546,800
3.325% Senior Unsecured Notes Due 2025 [Member]
Debt Instrument [Line Items]
Debt	[2]	579,000	610,800
2.500% Senior Unsecured Notes due 2026 [Member]
Debt Instrument [Line Items]
Debt	[2]	673,700
5.250% Senior Unsecured Notes Due 2026 [Member]
Debt Instrument [Line Items]
Debt		500,000	500,000
5.000% Senior Unsecured Notes Due 2027 [Member]
Debt Instrument [Line Items]
Debt		1,400,000	1,400,000
3.692% Senior Unsecured Notes due 2028 [Member]
Debt Instrument [Line Items]
Debt	[2]	808,440	820,200
4.625% Senior Unsecured Notes Due 2029 [Member]
Debt Instrument [Line Items]
Debt		900,000	900,000
3.375% Senior Unsecured Notes due 2030 [Member]
Debt Instrument [Line Items]
Debt	[2]	471,590
3.500% Senior Unsecured Notes due 2031 [Member]
Debt Instrument [Line Items]
Debt		$ 1,300,000	$ 1,300,000

[1] Includes £182 million and £121 million of GBP-denominated borrowings that reflect the exchange rate at September 30, 2021 and December 31, 2020, respectively.

[2] Non-U.S. dollar denominated debt reflects the exchange rate at September 30, 2021 and December 31, 2020.