Goodwill, Deferred Leasing Costs and Other Intangibles - Goodwill Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Dec. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Goodwill [Roll Forward]
Beginning balance	$ 1,374,809	$ 1,452,891	$ 1,514,561
Business combination		(7,134)	247,248
Impairment		(594,000)	(387,000)
Ending balance	$ 1,452,891	$ 851,757	$ 1,374,809

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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