Debt - Debt Summary (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Weighted Average Interest Rate	2.00%	2.20%
Debt	$ 16,518,126	$ 11,905,877
Credit Facilities [Member]
Debt Instrument [Line Items]
Weighted Average Interest Rate	0.40%	0.40%
Debt	$ 39,733	$ 184,255
Senior Notes [Member]
Debt Instrument [Line Items]
Weighted Average Interest Rate	2.10%	2.40%
Debt	$ 14,108,021	$ 9,660,570
Term Loans and Unsecured Other [Member]
Debt Instrument [Line Items]
Weighted Average Interest Rate	0.80%	0.90%
Debt	$ 1,723,473	$ 1,441,882
Secured Mortgage [Member]
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.60%	3.40%
Debt	$ 646,899	$ 619,170