SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	$ 97,100
Initial Cost
Land	139,397
Building and Improvements	449,782
Net Improvements (Write-Offs) Since Acquisition	48,026
Gross Amount at Which Carried
Land	139,397
Building and Improvements	497,808
Investments in real estate	637,205	$ 629,262
Accumulated Depreciation	131,165	120,555	$ 303,699	$ 271,055
Other disclosures
Federal tax cost basis (unaudited)	687,700
Office Building | 3601 S Congress Avenue Austin, TX
Initial Cost
Land	9,569
Building and Improvements	18,593
Net Improvements (Write-Offs) Since Acquisition	10,528
Gross Amount at Which Carried
Land	9,569
Building and Improvements	29,121
Investments in real estate	38,690
Accumulated Depreciation	8,075
Office Building | 1 Kaiser Plaza Oakland, CA
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	97,100
Initial Cost
Land	9,261
Building and Improvements	113,619
Net Improvements (Write-Offs) Since Acquisition	18,538
Gross Amount at Which Carried
Land	9,261
Building and Improvements	132,157
Investments in real estate	141,418
Accumulated Depreciation	47,775
Office Building | 2 Kaiser Plaza Parking Lot Oakland, CA
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	0
Initial Cost
Land	10,931
Building and Improvements	110
Net Improvements (Write-Offs) Since Acquisition	3,120
Gross Amount at Which Carried
Land	10,931
Building and Improvements	3,230
Investments in real estate	14,161
Accumulated Depreciation	32
Office Building | 11600 Wilshire Blvd Los Angeles, CA
Initial Cost
Land	3,477
Building and Improvements	18,522
Net Improvements (Write-Offs) Since Acquisition	1,954
Gross Amount at Which Carried
Land	3,477
Building and Improvements	20,476
Investments in real estate	23,953
Accumulated Depreciation	6,071
Office Building | 11620 Wilshire Blvd Los Angeles, CA
Initial Cost
Land	7,672
Building and Improvements	51,999
Net Improvements (Write-Offs) Since Acquisition	7,331
Gross Amount at Which Carried
Land	7,672
Building and Improvements	59,330
Investments in real estate	67,002
Accumulated Depreciation	17,011
Office Building | 4750 Wilshire Blvd Los Angeles, CA
Initial Cost
Land	16,633
Building and Improvements	28,985
Net Improvements (Write-Offs) Since Acquisition	5,067
Gross Amount at Which Carried
Land	16,633
Building and Improvements	34,052
Investments in real estate	50,685
Accumulated Depreciation	5,245
Office Building | Lindblade Media Center Los Angeles, CA
Initial Cost
Land	6,342
Building and Improvements	11,568
Net Improvements (Write-Offs) Since Acquisition	(101)
Gross Amount at Which Carried
Land	6,342
Building and Improvements	11,467
Investments in real estate	17,809
Accumulated Depreciation	1,832
Office Building | 1130 Howard Street San Francisco, CA
Initial Cost
Land	8,290
Building and Improvements	10,480
Net Improvements (Write-Offs) Since Acquisition	131
Gross Amount at Which Carried
Land	8,290
Building and Improvements	10,611
Investments in real estate	18,901
Accumulated Depreciation	966
Office Building | 9460 Wilshire Boulevard Los Angeles, CA
Initial Cost
Land	52,199
Building and Improvements	76,730
Net Improvements (Write-Offs) Since Acquisition	916
Gross Amount at Which Carried
Land	52,199
Building and Improvements	77,646
Investments in real estate	129,845
Accumulated Depreciation	6,686
Office Building | 1021 East 7th Street, Austin, TX
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	0
Initial Cost
Land	4,976
Building and Improvements	733
Net Improvements (Write-Offs) Since Acquisition	0
Gross Amount at Which Carried
Land	4,976
Building and Improvements	733
Investments in real estate	5,709
Accumulated Depreciation	9
Hotel | Sheraton Grand Hotel Sacramento, CA
Initial Cost
Land	3,497
Building and Improvements	107,447
Net Improvements (Write-Offs) Since Acquisition	320
Gross Amount at Which Carried
Land	3,497
Building and Improvements	107,767
Investments in real estate	111,264
Accumulated Depreciation	33,932
Hotel | Sheraton Grand Hotel Parking & Retail Sacramento, CA
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	0
Initial Cost
Land	6,550
Building and Improvements	10,996
Net Improvements (Write-Offs) Since Acquisition	222
Gross Amount at Which Carried
Land	6,550
Building and Improvements	11,218
Investments in real estate	17,768
Accumulated Depreciation	3,531
Line of Credit | Revolving Credit Facility
Other disclosures
Outstanding balance	$ 166,500	$ 153,000