SCHEDULE III REAL ESTATE ASSETS AND ACCUMULATED DEPRECIATION AND AMORTIZATION - Schedule of Assets, Depreciation and Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Real Estate and Accumulated Depreciation [Line Items]
Initial Cost to Company, Land	$ 229,962
Initial Cost to Company, Building and Improvements	1,672,887
Initial Cost to Company, Total	1,902,849
Cost Capitalized Subsequent to Acquisition	342,074
Gross Amount at which Carried at Close of Period, Land	226,106
Gross Amount at which Carried at Close of Period, Building and Improvements	2,018,817
Gross Amount at which Carried at Close of Period, Total	2,244,923	$ 2,552,979	$ 2,568,352	$ 2,441,266
Accumulated Depreciation and Amortization	(681,392)	$ (713,501)	$ (656,401)	$ (572,968)
Aggregate cost of real estate for federal income tax purposes	2,500,000
Secured Debt | Amended and Restated Portfolio Loan Facility
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	460,900
Secured Debt | Modified Portfolio Revolving Loan Facility
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	209,800
Mortgages | 3001 & 3003 Washington Mortgage Loan
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 138,800
Town Center
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Initial Cost to Company, Land	$ 7,428
Initial Cost to Company, Building and Improvements	108,547
Initial Cost to Company, Total	115,975
Cost Capitalized Subsequent to Acquisition	27,335
Gross Amount at which Carried at Close of Period, Land	7,428
Gross Amount at which Carried at Close of Period, Building and Improvements	135,882
Gross Amount at which Carried at Close of Period, Total	143,310
Accumulated Depreciation and Amortization	$ (58,514)
Gateway Tech Center
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Initial Cost to Company, Land	$ 5,617
Initial Cost to Company, Building and Improvements	20,051
Initial Cost to Company, Total	25,668
Cost Capitalized Subsequent to Acquisition	11,720
Gross Amount at which Carried at Close of Period, Land	5,617
Gross Amount at which Carried at Close of Period, Building and Improvements	31,771
Gross Amount at which Carried at Close of Period, Total	37,388
Accumulated Depreciation and Amortization	$ (14,095)
60 South Sixth
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Initial Cost to Company, Land	$ 16,951
Initial Cost to Company, Building and Improvements	109,191
Initial Cost to Company, Total	126,142
Cost Capitalized Subsequent to Acquisition	(10,622)
Gross Amount at which Carried at Close of Period, Land	16,003
Gross Amount at which Carried at Close of Period, Building and Improvements	99,517
Gross Amount at which Carried at Close of Period, Total	115,520
Accumulated Depreciation and Amortization	$ (1,825)
Sterling Plaza
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Initial Cost to Company, Land	$ 6,800
Initial Cost to Company, Building and Improvements	68,292
Initial Cost to Company, Total	75,092
Cost Capitalized Subsequent to Acquisition	21,994
Gross Amount at which Carried at Close of Period, Land	6,800
Gross Amount at which Carried at Close of Period, Building and Improvements	90,286
Gross Amount at which Carried at Close of Period, Total	97,086
Accumulated Depreciation and Amortization	$ (36,020)
Accenture Tower
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Encumbrances	$ 307,097
Initial Cost to Company, Land	49,306
Initial Cost to Company, Building and Improvements	370,662
Initial Cost to Company, Total	419,968
Cost Capitalized Subsequent to Acquisition	155,487
Gross Amount at which Carried at Close of Period, Land	49,306
Gross Amount at which Carried at Close of Period, Building and Improvements	526,149
Gross Amount at which Carried at Close of Period, Total	575,455
Accumulated Depreciation and Amortization	$ (184,634)
Ten Almaden
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Initial Cost to Company, Land	$ 7,000
Initial Cost to Company, Building and Improvements	110,292
Initial Cost to Company, Total	117,292
Cost Capitalized Subsequent to Acquisition	14,307
Gross Amount at which Carried at Close of Period, Land	7,000
Gross Amount at which Carried at Close of Period, Building and Improvements	124,599
Gross Amount at which Carried at Close of Period, Total	131,599
Accumulated Depreciation and Amortization	$ (45,433)
Towers at Emeryville
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Initial Cost to Company, Land	$ 35,774
Initial Cost to Company, Building and Improvements	147,167
Initial Cost to Company, Total	182,941
Cost Capitalized Subsequent to Acquisition	40,756
Gross Amount at which Carried at Close of Period, Land	35,774
Gross Amount at which Carried at Close of Period, Building and Improvements	187,923
Gross Amount at which Carried at Close of Period, Total	223,697
Accumulated Depreciation and Amortization	$ (73,665)
3003 Washington Boulevard
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Initial Cost to Company, Land	$ 18,800
Initial Cost to Company, Building and Improvements	129,820
Initial Cost to Company, Total	148,620
Cost Capitalized Subsequent to Acquisition	6,194
Gross Amount at which Carried at Close of Period, Land	18,800
Gross Amount at which Carried at Close of Period, Building and Improvements	136,014
Gross Amount at which Carried at Close of Period, Total	154,814
Accumulated Depreciation and Amortization	$ (49,418)
Park Place Village
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Encumbrances	$ 65,000
Initial Cost to Company, Land	11,009
Initial Cost to Company, Building and Improvements	117,070
Initial Cost to Company, Total	128,079
Cost Capitalized Subsequent to Acquisition	(40,243)
Gross Amount at which Carried at Close of Period, Land	8,101
Gross Amount at which Carried at Close of Period, Building and Improvements	79,735
Gross Amount at which Carried at Close of Period, Total	87,836
Accumulated Depreciation and Amortization	$ (17,430)
201 17th Street
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Initial Cost to Company, Land	$ 5,277
Initial Cost to Company, Building and Improvements	86,859
Initial Cost to Company, Total	92,136
Cost Capitalized Subsequent to Acquisition	13,371
Gross Amount at which Carried at Close of Period, Land	5,277
Gross Amount at which Carried at Close of Period, Building and Improvements	100,230
Gross Amount at which Carried at Close of Period, Total	105,507
Accumulated Depreciation and Amortization	$ (37,952)
515 Congress
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Initial Cost to Company, Land	$ 8,000
Initial Cost to Company, Building and Improvements	106,261
Initial Cost to Company, Total	114,261
Cost Capitalized Subsequent to Acquisition	23,214
Gross Amount at which Carried at Close of Period, Land	8,000
Gross Amount at which Carried at Close of Period, Building and Improvements	129,475
Gross Amount at which Carried at Close of Period, Total	137,475
Accumulated Depreciation and Amortization	$ (40,512)
The Almaden
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Encumbrances	$ 118,440
Initial Cost to Company, Land	29,000
Initial Cost to Company, Building and Improvements	130,145
Initial Cost to Company, Total	159,145
Cost Capitalized Subsequent to Acquisition	33,988
Gross Amount at which Carried at Close of Period, Land	29,000
Gross Amount at which Carried at Close of Period, Building and Improvements	164,133
Gross Amount at which Carried at Close of Period, Total	193,133
Accumulated Depreciation and Amortization	$ (56,081)
3001 Washington Boulevard
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Initial Cost to Company, Land	$ 9,900
Initial Cost to Company, Building and Improvements	41,551
Initial Cost to Company, Total	51,451
Cost Capitalized Subsequent to Acquisition	9,548
Gross Amount at which Carried at Close of Period, Land	9,900
Gross Amount at which Carried at Close of Period, Building and Improvements	51,099
Gross Amount at which Carried at Close of Period, Total	60,999
Accumulated Depreciation and Amortization	$ (16,648)
Carillon
Real Estate and Accumulated Depreciation [Line Items]
Ownership Percent	100.00%
Encumbrances	$ 88,140
Initial Cost to Company, Land	19,100
Initial Cost to Company, Building and Improvements	126,979
Initial Cost to Company, Total	146,079
Cost Capitalized Subsequent to Acquisition	35,025
Gross Amount at which Carried at Close of Period, Land	19,100
Gross Amount at which Carried at Close of Period, Building and Improvements	162,004
Gross Amount at which Carried at Close of Period, Total	181,104
Accumulated Depreciation and Amortization	$ (49,165)