Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value of Financial Instruments
Marketable securities	$ 29,524	$ 85,110
Interest rate cap and swap agreements (included in other assets)	14,323	21,090
Debt and preferred equity investments	1,986,413	1,640,412
Accrued Interest Payable And Other Liabilities
Fair Value of Financial Instruments
Interest rate cap and swap agreements		1
Carrying Value
Fair Value of Financial Instruments
Debt and preferred equity investments	1,986,413
Fixed rate debt	5,190,393	5,452,084
Variable rate debt	1,241,360	1,105,585
Total	6,431,753	6,557,669
Fair Value
Fair Value of Financial Instruments
Marketable securities	29,524	85,110
Total	6,591,477	6,832,604
Estimated fair value of debt and preferred equity investments, low end of range	2,000,000	1,600,000
Estimated fair value of debt and preferred equity investments, high end of range	2,200,000	1,800,000
Level 1
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)	0	0
Level 1 \| Accrued Interest Payable And Other Liabilities
Fair Value of Financial Instruments
Interest rate cap and swap agreements		0
Level 2
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)	14,323	21,090
Level 2 \| Accrued Interest Payable And Other Liabilities
Fair Value of Financial Instruments
Interest rate cap and swap agreements		1
Level 3
Fair Value of Financial Instruments
Marketable securities	0	0
Interest rate cap and swap agreements (included in other assets)	0	0
Level 3 \| Accrued Interest Payable And Other Liabilities
Fair Value of Financial Instruments
Interest rate cap and swap agreements		0
Level 3 \| Fair Value
Fair Value of Financial Instruments
Fixed rate debt	5,359,227	5,722,494
Variable rate debt	1,232,250	1,110,110
Equity marketable securities
Fair Value of Financial Instruments
Marketable securities	0	48,315
Equity marketable securities \| Level 1
Fair Value of Financial Instruments
Marketable securities	0	48,315
Commercial mortgage-backed securities
Fair Value of Financial Instruments
Marketable securities	29,524	36,795
Commercial mortgage-backed securities \| Level 2
Fair Value of Financial Instruments
Marketable securities	$ 29,524	$ 36,795

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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No definition available.

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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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-Publisher FASB
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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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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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- Definition

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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