Debt - Schedule of Debt (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)
Debt [Roll Forward]
Total debt, Beginning balance	$ 5,705,725
Debt Issuances, Net	831,846
Repayments, Extinguishment and Assumptions, Net	(232,337)
Accretion and Amortization, Net	1,367
Total debt, Ending balance	6,306,601
Mortgages [Member]
Debt [Roll Forward]
Outstanding balance, Beginning balance	1,529,057
Net premiums (discount), Beginning balance	6,861
Deferred costs, Beginning balance	(7,784)
Total debt, Beginning balance	1,528,134
Debt Issuances	913
Debt Issuances, Net	913
Repayments, Extinguishment and Assumptions	(122,199)
Repayments, Extinguishment and Assumptions of Debt, Premium	(202)
Repayments, Extinguishment and Assumptions of Debt, Deferred costs	64
Repayments, Extinguishment and Assumptions, Net	(122,337)
Accretion and Amortization	(1,536)
Accretion and Amortization, Deferred costs	527
Accretion and Amortization, Net	(1,009)
Outstanding balance, Ending balance	1,407,771
Net premiums (discount), Ending balance	5,123
Deferred costs, Ending balance	(7,193)
Total debt, Ending balance	1,405,701
Corporate Bonds [Member]
Debt [Roll Forward]
Outstanding balance, Beginning balance	2,850,000
Net premiums (discount), Beginning balance	(10,419)
Deferred costs, Beginning balance	(25,842)
Total debt, Beginning balance	2,813,739
Debt Issuances, Deferred costs	(380)
Accretion and Amortization	284
Accretion and Amortization, Deferred costs	831
Accretion and Amortization, Net	1,115
Outstanding balance, Ending balance	2,850,000
Net premiums (discount), Ending balance	(10,135)
Deferred costs, Ending balance	(25,391)
Total debt, Ending balance	2,814,474
Convertible Debt [Member]
Debt [Roll Forward]
Outstanding balance, Beginning balance	321,802
Net premiums (discount), Beginning balance	(1,855)
Deferred costs, Beginning balance	(1,764)
Total debt, Beginning balance	318,183
Accretion and Amortization	478
Accretion and Amortization, Deferred costs	459
Accretion and Amortization, Net	937
Outstanding balance, Ending balance	321,802
Net premiums (discount), Ending balance	(1,377)
Deferred costs, Ending balance	(1,305)
Total debt, Ending balance	319,120
Credit Facility [Member]
Debt [Roll Forward]
Outstanding balance, Beginning balance	1,050,000
Deferred costs, Beginning balance	(4,331)
Total debt, Beginning balance	1,045,669
Debt Issuances	831,313
Debt Issuances, Deferred costs	0
Debt Issuances, Net	831,313
Repayments, Extinguishment and Assumptions	(110,000)
Repayments, Extinguishment and Assumptions of Debt, Deferred costs	0
Repayments, Extinguishment and Assumptions, Net	(110,000)
Accretion and Amortization, Deferred costs	324
Accretion and Amortization, Net	324
Outstanding balance, Ending balance	1,771,313
Deferred costs, Ending balance	(4,007)
Total debt, Ending balance	$ 1,767,306