Summary of Significant Accounting Policies - Schedule of Material Changes Between Cash Flow Classifications due to Substantial Debt Prepayment Penalties (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Amortization of discounts and premiums on debt	$ 3,263	$ 1,391
Net (gain) loss on debt extinguishment	22,110	12,258
Net cash provided by operating activities	685,454	559,113
CASH FLOWS FROM INVESTING ACTIVITIES:
Net cash provided by (used for) investing activities	(84,176)	(44,607)
CASH FLOWS FROM FINANCING ACTIVITIES:
Commercial paper proceeds	4,766,050	2,610,863
Net cash (used for) financing activities	(613,163)	(420,481)
Cash and cash equivalents, beginning of period	50,647
Cash and cash equivalents and restricted deposits, beginning of period	100,762	219,088
Cash and cash equivalents, end of period	34,507	37,719
Cash and cash equivalents and restricted deposits, end of period	88,877	313,113
Scenario, Previously Reported [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Amortization of discounts and premiums on debt		3,359
(Increase) decrease in deposits - restricted		310
(Increase) decrease in mortgage deposits		900
Net cash provided by operating activities		550,033
CASH FLOWS FROM INVESTING ACTIVITIES:
(Increase) decrease in deposits on real estate acquisitions and investments, net		(177,742)
(Increase) decrease in mortgage deposits		(4,108)
Net cash provided by (used for) investing activities		(226,457)
CASH FLOWS FROM FINANCING ACTIVITIES:
Mortgage deposits		47,127
Commercial paper proceeds		2,608,895
Net cash (used for) financing activities		(363,064)
Cash and cash equivalents, beginning of period		77,207
Cash and cash equivalents, end of period		37,719
Reclassification Adjustments [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Amortization of discounts and premiums on debt		(1,968)
Net (gain) loss on debt extinguishment		12,258
(Increase) decrease in deposits - restricted		(310)
(Increase) decrease in mortgage deposits		(900)
Net cash provided by operating activities		9,080
CASH FLOWS FROM INVESTING ACTIVITIES:
(Increase) decrease in deposits on real estate acquisitions and investments, net		177,742
(Increase) decrease in mortgage deposits		4,108
Net cash provided by (used for) investing activities		181,850
CASH FLOWS FROM FINANCING ACTIVITIES:
Mortgage deposits		(47,127)
Commercial paper proceeds		1,968
Net cash (used for) financing activities		(57,417)
(adjustments for restricted deposits, beginning of period)		141,881
(adjustments for restricted deposits, end of period)		275,394
Mortgage Notes Payable, Net [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Mortgage notes payable, net: Net gain (loss) on debt extinguishment	$ (22,110)	(12,258)
Mortgage Notes Payable, Net [Member] \| Reclassification Adjustments [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Mortgage notes payable, net: Net gain (loss) on debt extinguishment		$ (12,258)

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