Schedule III - Real Estate and Accumulated Depreciation - Narrative (Details) $ in Thousands	12 Months Ended
Dec. 31, 2021 USD ($) ft² property project
Real Estate and Accumulated Depreciation [Line Items]
Initial cost, encumbrances	$ 249,023
Rentable square feet \| ft²	15,456,528
Investment in real estate, federal Income tax basis	$ 9,100,000
In-process development projects - under construction
Real Estate and Accumulated Depreciation [Line Items]
Number of buildings \| project	2
Rentable square feet \| ft²	946,000
Office Building
Real Estate and Accumulated Depreciation [Line Items]
Unamortized debt issuance expense	$ (700)
Office Building \| Sunset Blvd., Gower St. and El Centro Ave. Properties in Los Angeles
Real Estate and Accumulated Depreciation [Line Items]
Number of buildings \| property	5
Office Building \| 12100, 12200 and 12312 W. Olympic Blvd., Los Angeles, CA
Real Estate and Accumulated Depreciation [Line Items]
Initial cost, encumbrances	$ 163,435
Office Building \| 320 Westlake Ave. North, WA and 321 Terry Avenue North, Lake Union, WA
Real Estate and Accumulated Depreciation [Line Items]
Initial cost, encumbrances	$ 85,588
Residential Tower \| Sunset Blvd., Gower St. and El Centro Ave. Properties in Los Angeles
Real Estate and Accumulated Depreciation [Line Items]
Number of buildings \| property	1
Building
Real Estate and Accumulated Depreciation [Line Items]
Depreciation life	35 years
Tenant Improvements \| Minimum
Real Estate and Accumulated Depreciation [Line Items]
Property depreciable lives	1 year
Tenant Improvements \| Maximum
Real Estate and Accumulated Depreciation [Line Items]
Property depreciable lives	20 years

Amount of lien or mortgage outstanding on real estate investment properties for entities with a substantial portion of business acquiring and holding investment real estate.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Paragraph Column B
-Subsection 28

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 970
-SubTopic 360
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-28(Column B))
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Cost basis of real estate investments for federal income tax purposes for entities with a substantial portion of business acquiring and holding investment real estate.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Footnote 6
-Subsection 28

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-SubTopic 360
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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 10
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