Senior Unsecured Notes and Secured Debt - Summary of Principal Activity (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Amount
Beginning balance
Debt issued	$ 1,588,549	$ 3,253,516
Debt issued	44,921	318,854
Ending balance	13,882,465
Senior unsecured notes
Amount
Beginning balance	10,427,562	9,699,984
Debt issued	1,600,000	3,260,000
Debt extinguished	(566,248)	(3,107,500)
Foreign currency	(48,037)	(35,208)
Ending balance	$ 11,413,277	$ 9,817,276
Weighted Avg. Interest Rate
Beginning balance	4.03%	4.48%
Debt issued	0.0189	0.0347
Debt extinguished	0.0326	0.0447
Foreign currency	0.0414	0.0435
Ending balance	3.67%	4.12%
Secured debt
Amount
Beginning balance	$ 2,993,342	$ 2,485,711
Debt issued	44,921	318,854
Debt assumed	0	42,000
Debt extinguished	(491,506)	(193,604)
Principal payments	(46,585)	(40,348)
Foreign currency	(30,984)	26,402
Ending balance	$ 2,469,188	$ 2,639,015
Weighted Avg. Interest Rate
Beginning balance	3.63%	3.90%
Debt issued	0.0258	0.0351
Debt assumed	0	0.0462
Debt extinguished	0.0261	0.0437
Principal payments	0.0360	0.0369
Foreign currency	0.0319	0.0320
Ending balance	3.16%	3.66%