REAL ESTATE - Schedule of Real Estate Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Real Estate Properties [Line Items]
Total real estate held for investment, cost	$ 1,861,466	$ 2,060,002
Accumulated depreciation and amortization	(559,269)	(627,942)
Total real estate held for investment, net	1,302,197	$ 1,432,060
Town Center \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	147,694
Accumulated depreciation and amortization	(65,259)
Total real estate held for investment, net	82,435
Gateway Tech Center \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	37,935
Accumulated depreciation and amortization	(15,826)
Total real estate held for investment, net	22,109
60 South Sixth \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	88,241
Accumulated depreciation and amortization	(1,448)
Total real estate held for investment, net	86,793
Accenture Tower \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	580,977
Accumulated depreciation and amortization	(208,066)
Total real estate held for investment, net	372,911
Ten Almaden \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	131,720
Accumulated depreciation and amortization	(50,073)
Total real estate held for investment, net	81,647
Towers at Emeryville \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	128,576
Accumulated depreciation and amortization	(1,260)
Total real estate held for investment, net	127,316
3003 Washington Boulevard \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	154,908
Accumulated depreciation and amortization	(53,735)
Total real estate held for investment, net	101,173
201 17th Street \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	105,854
Accumulated depreciation and amortization	(42,313)
Total real estate held for investment, net	63,541
515 Congress \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	139,164
Accumulated depreciation and amortization	(45,668)
Total real estate held for investment, net	93,496
The Almaden \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	103,357
Accumulated depreciation and amortization	(1,230)
Total real estate held for investment, net	102,127
3001 Washington Boulevard \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	61,048
Accumulated depreciation and amortization	(18,518)
Total real estate held for investment, net	42,530
Carillon \| Office Building
Real Estate Properties [Line Items]
Total real estate held for investment, cost	181,992
Accumulated depreciation and amortization	(55,873)
Total real estate held for investment, net	$ 126,119

Real Estate Investment Property, Excluding Held-For-Sale

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- Definition

The cumulative amount of depreciation for real estate property held for investment purposes.

+ References

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- Definition

Amount of real estate investment property which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(d))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(6))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

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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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