Debt - Debt Summary (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Weighted Average Interest Rate	1.90%	2.20%
Weighted Average Term	10.2	7.8
Debt	$ 16,849,076	$ 11,905,877
Credit Facilities [Member]
Debt Instrument [Line Items]
Weighted Average Interest Rate	0.80%	0.40%
Weighted Average Term	2.0	1.1
Debt	$ 171,794	$ 184,255
Senior Notes [Member]
Debt Instrument [Line Items]
Weighted Average Interest Rate	2.00%	2.40%
Weighted Average Term	11.2	8.2
Debt	$ 14,275,870	$ 9,660,570
Term Loans and Unsecured Other [Member]
Debt Instrument [Line Items]
Weighted Average Interest Rate	0.90%	0.90%
Weighted Average Term	5.6	7.5
Debt	$ 1,764,311	$ 1,441,882
Secured Mortgage [Member]
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.10%	3.40%
Weighted Average Term	3.0	4.0
Debt	$ 637,101	$ 619,170