Fair value of investment other than investment in equity security, investment in debt security and equity method investment. Includes, but is not limited to, investment in certain entities that calculate net asset value per share. Example includes, but is not limited to, investment in hedge fund, venture capital fund, private equity fund, and real estate partnership or fund.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 6A
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Topic 820
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Area of a real estate property.

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- Definition

Amount of funds committed to investment company from investors.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 946
-SubTopic 205
-Section 50
-Paragraph 25
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Cash received from the sale of real estate that is held for investment, that is, it is part of an investing activity during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
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Investments in Unconsolidated Real Estate Funds - Additional Information (Details)		1 Months Ended	3 Months Ended
	Jan. 25, 2019 USD ($) ft²	Dec. 31, 2018 USD ($)	Mar. 31, 2019 USD ($) ft²
Investment Holdings [Line Items]
Area of office and retail properties \| ft²			12,200,000
Fund VII and VII-H [Member] \| Office Building [Member]
Investment Holdings [Line Items]
Area of office and retail properties \| ft²	64,532
Fund VII and VII-H [Member] \| Zero Bond Street [Member]
Investment Holdings [Line Items]
Proceeds from sale of real estate	$ 130,500,000
Fund VIII [Member]
Investment Holdings [Line Items]
Capital commitments			$ 157,950,000
Capital commitments invested			$ 617,250,000
Fund X [Member]
Investment Holdings [Line Items]
Capital commitments		$ 167,000,000