Debt - Schedule of Debt (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($)
Debt [Roll Forward]
Total debt, Beginning balance	$ 5,705,725
Debt Issuances, Net	1,491,988
Repayments, Extinguishment and Assumptions, Net	(1,235,704)
Accretion and Amortization, Net	3,044
Total debt, Ending balance	5,965,053
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, Net	1,032
Repayments, Extinguishment and Assumptions	(133,657)
Repayments, Extinguishment and Assumptions of Debt, Premium	(216)
Repayments, Extinguishment and Assumptions of Debt, Deferred costs	65
Repayments, Extinguishment and Assumptions, Net	(133,808)
Accretion and Amortization	(2,760)
Accretion and Amortization, Deferred costs	1,054
Accretion and Amortization, Net	(1,706)
Outstanding balance, Ending balance	1,396,432
Net premiums (discount), Ending balance	3,885
Deferred costs, Ending balance	(6,665)
Total debt, Ending balance	1,393,652
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	571
Accretion and Amortization, Deferred costs	1,669
Accretion and Amortization, Net	2,240
Outstanding balance, Ending balance	3,450,000
Net premiums (discount), Ending balance	(14,984)
Deferred costs, Ending balance	(30,081)
Total debt, Ending balance	3,404,935
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	(50,169)
Repayments, Extinguishment and Assumptions of Debt, Discount	140
Repayments, Extinguishment and Assumptions of Debt, Deferred costs	133
Repayments, Extinguishment and Assumptions, Net	(49,896)
Accretion and Amortization	954
Accretion and Amortization, Deferred costs	911
Accretion and Amortization, Net	1,865
Outstanding balance, Ending balance	271,633
Net premiums (discount), Ending balance	(761)
Deferred costs, Ending balance	(720)
Total debt, Ending balance	270,152
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, Net	902,000
Repayments, Extinguishment and Assumptions	(1,052,000)
Repayments, Extinguishment and Assumptions, Net	(1,052,000)
Accretion and Amortization, Deferred costs	645
Accretion and Amortization, Net	645
Outstanding balance, Ending balance	900,000
Deferred costs, Ending balance	(3,686)
Total debt, Ending balance	$ 896,314