Schedule III - Real Estate and Accumulated Depreciation and Amortization - (Parenthetical) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) Property	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Land, buildings, and leasehold interests:
Beginning balance	$ 8,534,275	$ 8,448,702	$ 7,883,633
Acquisitions and dollars invested in projects under construction and tenant improvements	551,287	177,901	733,376
Dispositions	(146,019)	(54,886)	(138,332)
Impairment losses	(21,957)	(37,442)	(29,975)
Ending balance	8,917,586	8,534,275	8,448,702
Accumulated depreciation and amortization:
Beginning balance	1,319,943	1,151,667	1,016,271
Dispositions	(44,509)	(17,828)	(44,185)
Depreciation and amortization expense	195,959	186,104	179,581
Ending balance	1,471,393	1,319,943	$ 1,151,667
Net investment in direct financing leases	3,653	3,994
Real estate, federal income tax basis	8,828,431
Mortgages payable, including unamortized premium and net of unamortized debt costs	10,697	$ 11,395
Mortgages [Member]
Accumulated depreciation and amortization:
Mortgages payable, including unamortized premium and net of unamortized debt costs	10,719
Mortgage Agreement
Accumulated depreciation and amortization:
Mortgages payable, including unamortized premium and net of unamortized debt costs	15,151
Unamortized Discount (Premium) and Debt Issuance Costs	$ 10,697
Mortgage Agreement | Mortgages [Member]
Accumulated depreciation and amortization:
Number Of Properties Securing Mortgages Payable | Property	5