Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

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- Definition

The amount of revenue derived from managing real estate properties.

+ References

No definition available.

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- Definition

The carrying amount of investments in unconsolidated real estate and other joint ventures not separately presented. This includes direct and indirect investments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(d))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

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- Definition

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.

+ References

No definition available.

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Investments in Unconsolidated Real Estate Ventures - Summary of Composition of Investments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures	$ 455,476		$ 461,369
Difference between the investments in unconsolidated real estate ventures and the net book value of the underlying assets	$ 19,500		18,900
Prudential Global Investment Management (PGIM)
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)	50.00%
Total investments in unconsolidated real estate ventures	$ 212,796		216,939
Landmark
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures	$ 65,313		66,724
Landmark \| Minimum
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)	1.80%
Landmark \| Maximum
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)	49.00%
CBREI Venture
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures	$ 64,251		65,190
CBREI Venture \| Minimum
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)	5.00%
CBREI Venture \| Maximum
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)	64.00%
Canadian Pension Plan Investment Board (CPPIB)
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)	55.00%
Total investments in unconsolidated real estate ventures	$ 47,072		47,522
Berkshire Group
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)	50.00%
Total investments in unconsolidated real estate ventures	$ 51,662		50,649
Brandywine Realty Trust
Schedule of Equity Method Investments [Line Items]
Ownership interest (as percent)	30.00%
Total investments in unconsolidated real estate ventures	$ 13,751		13,710
Other
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures	631		635
Investments in Unconsolidated Real Estate Ventures
Schedule of Equity Method Investments [Line Items]
Property Management Fee Revenue	5,900	$ 6,700
1101 17th Street \| Canadian Pension Plan Investment Board (CPPIB)
Schedule of Equity Method Investments [Line Items]
Total investments in unconsolidated real estate ventures	$ 0		$ 0