SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	$ 532,437
Initial Cost
Land	343,564
Building and Improvements	1,552,411
Net Improvements (Write-Offs) Since Acquisition	125,519
Gross Amount at Which Carried
Land	343,564
Building and Improvements	1,677,930
Investments in real estate	2,021,494	$ 2,061,372
Accumulated Depreciation	414,552	$ 369,661	$ 320,857	$ 271,683
Other disclosures
Federal tax cost basis (unaudited)	2,036,225
Office | 7083 Hollywood Blvd Los Angeles, CA
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	21,700
Initial Cost
Land	6,276
Building and Improvements	13,161
Net Improvements (Write-Offs) Since Acquisition	3,248
Gross Amount at Which Carried
Land	6,276
Building and Improvements	16,409
Investments in real estate	22,685
Accumulated Depreciation	5,626
Office | 800 N Capitol Street Washington, DC
Initial Cost
Building and Improvements	109,948
Net Improvements (Write-Offs) Since Acquisition	(6,685)
Gross Amount at Which Carried
Building and Improvements	103,263
Investments in real estate	103,263
Accumulated Depreciation	28,168
Office | 370 L'Enfant Prom Washington, DC
Initial Cost
Land	33,936
Building and Improvements	145,796
Net Improvements (Write-Offs) Since Acquisition	(5,724)
Gross Amount at Which Carried
Land	33,936
Building and Improvements	140,072
Investments in real estate	174,008
Accumulated Depreciation	39,969
Office | 260 Townsend San Francisco, CA
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	28,200
Initial Cost
Land	7,574
Building and Improvements	13,843
Net Improvements (Write-Offs) Since Acquisition	2,219
Gross Amount at Which Carried
Land	7,574
Building and Improvements	16,062
Investments in real estate	23,636
Accumulated Depreciation	6,603
Office | 830 1st Street Washington, DC
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	46,000
Initial Cost
Land	18,095
Building and Improvements	62,017
Net Improvements (Write-Offs) Since Acquisition	(1,193)
Gross Amount at Which Carried
Land	18,095
Building and Improvements	60,824
Investments in real estate	78,919
Accumulated Depreciation	15,939
Office | 200 S College Street Charlotte, NC
Initial Cost
Land	7,702
Building and Improvements	109,006
Net Improvements (Write-Offs) Since Acquisition	8,497
Gross Amount at Which Carried
Land	7,702
Building and Improvements	117,503
Investments in real estate	125,205
Accumulated Depreciation	35,792
Office | 3601 S Congress Avenue Austin, TX
Initial Cost
Land	9,569
Building and Improvements	18,593
Net Improvements (Write-Offs) Since Acquisition	1,900
Gross Amount at Which Carried
Land	9,569
Building and Improvements	20,493
Investments in real estate	30,062
Accumulated Depreciation	6,459
Office | 899 N Capitol Street Washington, DC
Initial Cost
Land	34,641
Building and Improvements	84,466
Net Improvements (Write-Offs) Since Acquisition	12,638
Gross Amount at Which Carried
Land	34,641
Building and Improvements	97,104
Investments in real estate	131,745
Accumulated Depreciation	24,517
Office | 999 N Capitol Street Washington, DC
Initial Cost
Land	32,221
Building and Improvements	86,526
Net Improvements (Write-Offs) Since Acquisition	10,710
Gross Amount at Which Carried
Land	32,221
Building and Improvements	97,236
Investments in real estate	129,457
Accumulated Depreciation	25,564
Office | 901 N Capitol Street Washington, DC
Initial Cost
Land	27,117
Net Improvements (Write-Offs) Since Acquisition	4,299
Gross Amount at Which Carried
Land	27,117
Building and Improvements	4,299
Investments in real estate	31,416
Accumulated Depreciation	1,216
Office | 1333 Broadway Oakland, CA
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	39,500
Initial Cost
Land	7,048
Building and Improvements	41,578
Net Improvements (Write-Offs) Since Acquisition	9,910
Gross Amount at Which Carried
Land	7,048
Building and Improvements	51,488
Investments in real estate	58,536
Accumulated Depreciation	12,128
Office | 1901 Harrison Street Oakland, CA
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	42,500
Initial Cost
Land	3,838
Building and Improvements	68,106
Net Improvements (Write-Offs) Since Acquisition	5,792
Gross Amount at Which Carried
Land	3,838
Building and Improvements	73,898
Investments in real estate	77,736
Accumulated Depreciation	19,870
Office | 2100 Franklin Street Oakland, CA
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	80,000
Initial Cost
Land	4,277
Building and Improvements	34,033
Net Improvements (Write-Offs) Since Acquisition	11,638
Gross Amount at Which Carried
Land	4,277
Building and Improvements	45,671
Investments in real estate	49,948
Accumulated Depreciation	13,100
Office | 2101 Webster Street Oakland, CA
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	83,000
Initial Cost
Land	4,752
Building and Improvements	109,812
Net Improvements (Write-Offs) Since Acquisition	31,111
Gross Amount at Which Carried
Land	4,752
Building and Improvements	140,923
Investments in real estate	145,675
Accumulated Depreciation	35,951
Office | 2353 Webster Street Parking Garage Oakland, CA
Initial Cost
Building and Improvements	9,138
Net Improvements (Write-Offs) Since Acquisition	29
Gross Amount at Which Carried
Building and Improvements	9,167
Investments in real estate	9,167
Accumulated Depreciation	1,894
Office | 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	16,677
Gross Amount at Which Carried
Land	9,261
Building and Improvements	130,296
Investments in real estate	139,557
Accumulated Depreciation	32,194
Office | 2 Kaiser Plaza Parking Lot Oakland, CA
Initial Cost
Land	10,931
Building and Improvements	110
Net Improvements (Write-Offs) Since Acquisition	653
Gross Amount at Which Carried
Land	10,931
Building and Improvements	763
Investments in real estate	11,694
Accumulated Depreciation	29
Office | 980 9th Street Sacramento, CA
Initial Cost
Land	3,380
Building and Improvements	86,939
Net Improvements (Write-Offs) Since Acquisition	4,375
Gross Amount at Which Carried
Land	3,380
Building and Improvements	91,314
Investments in real estate	94,694
Accumulated Depreciation	17,760
Office | 1010 8th Street Parking Garage & Retail Sacramento, CA
Initial Cost
Land	1,020
Building and Improvements	1,980
Net Improvements (Write-Offs) Since Acquisition	148
Gross Amount at Which Carried
Land	1,020
Building and Improvements	2,128
Investments in real estate	3,148
Accumulated Depreciation	414
Office | 211 Main Street San Francisco, CA
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	26,136
Initial Cost
Land	14,364
Building and Improvements	106,875
Net Improvements (Write-Offs) Since Acquisition	1,837
Gross Amount at Which Carried
Land	14,364
Building and Improvements	108,712
Investments in real estate	123,076
Accumulated Depreciation	28,994
Office | 11600 Wilshire Blvd Los Angeles, CA
Initial Cost
Land	3,477
Building and Improvements	18,522
Net Improvements (Write-Offs) Since Acquisition	1,650
Gross Amount at Which Carried
Land	3,477
Building and Improvements	20,172
Investments in real estate	23,649
Accumulated Depreciation	3,707
Office | 11620 Wilshire Blvd Los Angeles, CA
Initial Cost
Land	7,672
Building and Improvements	51,999
Net Improvements (Write-Offs) Since Acquisition	7,678
Gross Amount at Which Carried
Land	7,672
Building and Improvements	59,677
Investments in real estate	67,349
Accumulated Depreciation	11,123
Office | 4750 Wilshire Blvd Los Angeles, CA
Initial Cost
Land	16,633
Building and Improvements	28,985
Net Improvements (Write-Offs) Since Acquisition	58
Gross Amount at Which Carried
Land	16,633
Building and Improvements	29,043
Investments in real estate	45,676
Accumulated Depreciation	2,341
Office | Lindblade Media Center Los Angeles, CA
Initial Cost
Land	6,342
Building and Improvements	11,568
Gross Amount at Which Carried
Land	6,342
Building and Improvements	11,568
Investments in real estate	17,910
Accumulated Depreciation	847
Multifamily | 3636 McKinney Avenue Dallas, TX
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	9,363
Initial Cost
Land	3,806
Building and Improvements	11,077
Net Improvements (Write-Offs) Since Acquisition	427
Gross Amount at Which Carried
Land	3,806
Building and Improvements	11,504
Investments in real estate	15,310
Accumulated Depreciation	2,021
Multifamily | 3839 McKinney Avenue Dallas, TX
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	6,211
Initial Cost
Land	1,679
Building and Improvements	8,621
Net Improvements (Write-Offs) Since Acquisition	254
Gross Amount at Which Carried
Land	1,679
Building and Improvements	8,875
Investments in real estate	10,554
Accumulated Depreciation	1,577
Multifamily | 4649 Cole Avenue Dallas, TX
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	23,560
Initial Cost
Land	17,483
Building and Improvements	16,355
Net Improvements (Write-Offs) Since Acquisition	5,420
Gross Amount at Which Carried
Land	17,483
Building and Improvements	21,775
Investments in real estate	39,258
Accumulated Depreciation	4,191
Multifamily | 4200 Scotland Street Houston, TX
SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	29,167
Initial Cost
Land	9,811
Building and Improvements	40,150
Net Improvements (Write-Offs) Since Acquisition	343
Gross Amount at Which Carried
Land	9,811
Building and Improvements	40,493
Investments in real estate	50,304
Accumulated Depreciation	7,030
Multifamily | 47 E 34th Street New York, NY
Initial Cost
Land	30,612
Building and Improvements	31,145
Net Improvements (Write-Offs) Since Acquisition	1,450
Gross Amount at Which Carried
Land	30,612
Building and Improvements	32,595
Investments in real estate	63,207
Accumulated Depreciation	4,226
Hotel | Sheraton Grand Hotel Sacramento, CA
Initial Cost
Land	3,497
Building and Improvements	107,447
Net Improvements (Write-Offs) Since Acquisition	(3,729)
Gross Amount at Which Carried
Land	3,497
Building and Improvements	103,718
Investments in real estate	107,215
Accumulated Depreciation	22,899
Hotel | Sheraton Grand Hotel Parking & Retail Sacramento, CA
Initial Cost
Land	6,550
Building and Improvements	10,996
Net Improvements (Write-Offs) Since Acquisition	(111)
Gross Amount at Which Carried
Land	6,550
Building and Improvements	10,885
Investments in real estate	17,435
Accumulated Depreciation	$ 2,403