Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair Value of Financial Instruments
Marketable securities available-for-sale	$ 24,289	$ 28,570
Interest rate cap and swap agreements (included in Other assets)	275	28
Debt and preferred equity investments	1,072,711	1,076,542
Equity method investments	3,209,151	3,823,322
Additional amount of financing receivables included in other assets	66,400	66,200
Carrying Value
Fair Value of Financial Instruments
Debt and preferred equity investments	1,072,711	1,076,542
Fixed rate debt	3,930,094	3,135,572
Variable rate debt	795,902	1,827,677
Total	4,725,996	4,963,249
Fair Value
Fair Value of Financial Instruments
Marketable securities available-for-sale	24,289	28,570
Total	4,815,635	5,059,815
Estimated fair value of debt and preferred equity investments, low end of range	1,000,000	1,000,000
Estimated fair value of debt and preferred equity investments, high end of range	1,100,000	1,100,000
Level 1
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in Other assets)	0	0
Level 2
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in Other assets)	275	28
Level 3
Fair Value of Financial Instruments
Marketable securities available-for-sale	0	0
Interest rate cap and swap agreements (included in Other assets)	0	0
Level 3 \| Fair Value
Fair Value of Financial Instruments
Fixed rate debt	4,014,621	3,237,075
Variable rate debt	801,014	1,822,740
Equity Securities \| Level 1
Fair Value of Financial Instruments
Marketable securities available-for-sale	0	0
Commercial mortgage-backed securities
Fair Value of Financial Instruments
Marketable securities available-for-sale	24,289	28,570
Commercial mortgage-backed securities \| Level 2
Fair Value of Financial Instruments
Marketable securities available-for-sale	24,289	28,570
Joint venture
Fair Value of Financial Instruments
Equity method investments	3,209,151
Accrued Interest Payable And Other
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in Other liabilities)	44,912	61,217
Accrued Interest Payable And Other \| Level 1
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in Other liabilities)	0	0
Accrued Interest Payable And Other \| Level 2
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in Other liabilities)	44,912	61,217
Accrued Interest Payable And Other \| Level 3
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in Other liabilities)	$ 0	$ 0

Represents the amount of financing receivables recorded in other assets on the entity's balance sheet.

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Represents the high end of the range of estimated fair value for investments in mortgage loans on real estate.

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Represents the low end of the range of estimated fair value for investments in mortgage loans on real estate.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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The portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

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The portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

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The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

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