Goodwill and Other Intangibles - Intangible Assets and Liabilities Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Amortizable Intangible Assets
Accumulated Amortization	$ (1,374,102)	$ (1,287,668)
Indefinite Lived Intangible Assets Including Goodwill
Total intangible assets, gross	4,082,514	3,996,740
Total intangible assets, net	2,708,412	2,709,072
Amortizable Intangible Liabilities
Less: accumulated amortization	97,348	90,193
Indefinite Lived Intangible Liabilities
Total intangible liabilities, gross	(294,415)	(287,441)
Total intangible liabilities, net	(197,067)	(197,248)
Below-market purchase option
Indefinite Lived Intangible Liabilities
Indefinite-lived intangible liabilities	(16,711)	(16,711)
Below-market rent
Amortizable Intangible Liabilities
Finite-lived intangible liabilities, gross	(277,704)	(270,730)
Less: accumulated amortization	97,348	90,193
Net amortizable intangible liabilities	(180,356)	(180,537)
Goodwill
Indefinite Lived Intangible Assets Including Goodwill
Indefinite-lived intangible assets	907,295	910,818
Contracts including internal software development costs
Amortizable Intangible Assets
Gross Carrying Amount	23,308	23,179
Accumulated Amortization	(20,303)	(18,497)
Net Carrying Amount	3,005	4,682
Internal-use software development costs
Amortizable Intangible Assets
Gross Carrying Amount	19,333	19,204
Accumulated Amortization	(17,119)	(15,711)
Net Carrying Amount	2,214	3,493
Trade name
Amortizable Intangible Assets
Gross Carrying Amount	3,975	3,975
Accumulated Amortization	(3,184)	(2,786)
Net Carrying Amount	791	1,189
Lease intangibles
Amortizable Intangible Assets
Gross Carrying Amount	3,151,911	3,062,743
Accumulated Amortization	(1,353,799)	(1,269,171)
Net Carrying Amount	1,798,112	1,793,572
In-place lease
Amortizable Intangible Assets
Gross Carrying Amount	2,282,941	2,181,584
Accumulated Amortization	(884,875)	(828,219)
Net Carrying Amount	1,398,066	1,353,365
Above-market rent
Amortizable Intangible Assets
Gross Carrying Amount	868,970	881,159
Accumulated Amortization	(468,924)	(440,952)
Net Carrying Amount	$ 400,046	$ 440,207