Debt - Notes - Summary of Notes Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Notes, net beginning balance	$ 6,077,513	$ 5,933,286
Proceeds		1,194,468	$ 896,294
Lump sum payoffs	(750,000)	(1,050,000)
Realized/unrealized (gain) loss on derivative instruments		2,277	(680)
Amortization of premiums/ discounts	2,997	3,162	2,637
Amortization of deferred financing costs, net		(5,680)
Notes, net ending balance	5,335,536	6,077,513	5,933,286
Fixed Rate Debt [Member] | Unsecured – Public [Member]
Debt Instrument [Line Items]
Notes, net beginning balance	6,077,513	5,485,884
Proceeds		1,194,468
Lump sum payoffs	(750,000)	(600,000)
Amortization of premiums/ discounts	2,997	3,117
Amortization of deferred financing costs, net	5,026	(5,956)
Notes, net ending balance	$ 5,335,536	6,077,513	5,485,884
Floating Rate Debt [Member] | Unsecured – Public [Member]
Debt Instrument [Line Items]
Notes, net beginning balance		447,402
Lump sum payoffs		(450,000)
Realized/unrealized (gain) loss on derivative instruments		2,277
Amortization of premiums/ discounts		45
Amortization of deferred financing costs, net		$ 276
Notes, net ending balance			$ 447,402