Goodwill and Other Intangibles - Intangible Assets and Liabilities Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Amortizable Intangible Assets
Less: accumulated amortization	$ (1,143,648)	$ (1,089,784)
Indefinite Lived Intangible Assets Including Goodwill
Total intangible assets, gross	3,922,783	3,940,026
Total intangible assets, net	2,779,135	2,850,242
Amortizable Intangible Liabilities
Less: accumulated amortization	80,302	74,484
Indefinite Lived Intangible Liabilities
Total intangible liabilities, gross	(282,810)	(285,226)
Total intangible liabilities, net	(202,508)	(210,742)
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	(266,099)	(268,515)
Less: accumulated amortization	80,302	74,484
Net amortizable intangible liabilities	(185,797)	(194,031)
Goodwill
Indefinite Lived Intangible Assets Including Goodwill
Indefinite-lived intangible assets	929,887	934,688
Contracts including internal software development costs
Amortizable Intangible Assets
Finite lived intangible assets, gross	23,607	23,557
Less: accumulated amortization	(16,423)	(15,482)
Amortizable intangible assets	7,184	8,075
Internal-use software development costs
Amortizable Intangible Assets
Finite lived intangible assets, gross	19,632	19,582
Less: accumulated amortization	(14,233)	(13,491)
Amortizable intangible assets	5,399	6,091
Trade name
Amortizable Intangible Assets
Finite lived intangible assets, gross	3,975	3,975
Less: accumulated amortization	(2,190)	(1,991)
Amortizable intangible assets	1,785	1,984
Lease intangibles
Amortizable Intangible Assets
Finite lived intangible assets, gross	2,969,289	2,981,781
Less: accumulated amortization	(1,127,225)	(1,074,302)
Amortizable intangible assets	1,842,064	1,907,479
In-place lease
Amortizable Intangible Assets
Finite lived intangible assets, gross	2,071,324	2,072,642
Less: accumulated amortization	(714,713)	(676,008)
Amortizable intangible assets	1,356,611	1,396,634
Above-market rent
Amortizable Intangible Assets
Finite lived intangible assets, gross	897,965	909,139
Less: accumulated amortization	(412,512)	(398,294)
Amortizable intangible assets	$ 485,453	$ 510,845