Debt - Schedule of Debt (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Debt [Roll Forward]
Total debt, Beginning balance	$ 5,705,725
Debt Issuances, Net	1,491,657
Repayments, Extinguishment and Assumptions, Net	(1,317,120)
Accretion and Amortization, Net	5,008
Total debt, Ending balance	5,885,270
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	1,032
Debt Issuances, Deferred costs	(326)
Debt Issuances, Net	706
Repayments, Extinguishment and Assumptions	(195,991)
Repayments, Extinguishment and Assumptions of Debt, Premium	(415)
Repayments, Extinguishment and Assumptions of Debt, Deferred costs	65
Repayments, Extinguishment and Assumptions, Net	(196,341)
Accretion and Amortization	(3,915)
Accretion and Amortization, Deferred costs	1,590
Accretion and Amortization, Net	(2,325)
Outstanding balance, Ending balance	1,334,098
Net premiums (discount), Ending balance	2,531
Deferred costs, Ending balance	(6,455)
Total debt, Ending balance	1,330,174
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	600,000
Debt Issuance, Discount	(5,136)
Debt Issuances, Deferred costs	(5,908)
Debt Issuances, Net	588,956
Accretion and Amortization	1,012
Accretion and Amortization, Deferred costs	2,682
Accretion and Amortization, Net	3,694
Outstanding balance, Ending balance	3,450,000
Net premiums (discount), Ending balance	(14,543)
Deferred costs, Ending balance	(29,068)
Total debt, Ending balance	3,406,389
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
Repayments, Extinguishment and Assumptions	(69,083)
Repayments, Extinguishment and Assumptions of Debt, Discount	156
Repayments, Extinguishment and Assumptions of Debt, Deferred costs	148
Repayments, Extinguishment and Assumptions, Net	(68,779)
Accretion and Amortization	1,368
Accretion and Amortization, Deferred costs	1,305
Accretion and Amortization, Net	2,673
Outstanding balance, Ending balance	252,719
Net premiums (discount), Ending balance	(331)
Deferred costs, Ending balance	(311)
Total debt, Ending balance	252,077
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	902,000
Debt Issuances, Deferred costs	(5)
Debt Issuances, Net	901,995
Repayments, Extinguishment and Assumptions	(1,052,000)
Repayments, Extinguishment and Assumptions, Net	(1,052,000)
Accretion and Amortization, Deferred costs	966
Accretion and Amortization, Net	966
Outstanding balance, Ending balance	900,000
Deferred costs, Ending balance	(3,370)
Total debt, Ending balance	$ 896,630