Real Estate Investments And Accumulated Depreciation (Schedule Of Real Estate Investments And Accumulated Depreciation) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Related Encumbrances		$ 667,076
Initial Costs, Land		796,691
Initial Costs, Building and Improvements		3,531,729
Costs Capitalized Subsequent to Acquisition		479,298
Gross Amount at Which Carried at Close of Period, Land	[1]	735,696
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,072,022
Total		4,807,718		$ 4,958,179	$ 5,129,933	$ 5,379,436
Accumulated depreciation		1,464,482	[2]	$ 1,414,305	$ 1,400,988	$ 1,478,214
Real Estate Aggregate Cost, Tax Purpose		$ 3,300,000
Office [Member] | One Bridge Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1981
Acquired		1996
Initial Costs, Land		$ 2,439
Initial Costs, Building and Improvements		24,462
Costs Capitalized Subsequent to Acquisition		7,444
Gross Amount at Which Carried at Close of Period, Land	[3]	2,439
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	31,906
Total		34,345
Accumulated depreciation	[2]	$ 14,813
Office [Member] | 2115 Linwood Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1981
Acquired		1998
Initial Costs, Land		$ 474
Initial Costs, Building and Improvements		4,419
Costs Capitalized Subsequent to Acquisition		7,017
Gross Amount at Which Carried at Close of Period, Land	[3]	474
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	11,436
Total		11,910
Accumulated depreciation	[2]	$ 4,083
Office [Member] | 135 Chestnut Ridge Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1981
Acquired		1997
Initial Costs, Land		$ 2,587
Initial Costs, Building and Improvements		10,350
Costs Capitalized Subsequent to Acquisition		(4,659)
Gross Amount at Which Carried at Close of Period, Land	[3]	1,437
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	6,841
Total		8,278
Accumulated depreciation	[2]	$ 3,026
Office [Member] | 15 East Midland Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		1997
Related Encumbrances		$ 12,438
Initial Costs, Land		10,375
Initial Costs, Building and Improvements		41,497
Costs Capitalized Subsequent to Acquisition		2,490
Gross Amount at Which Carried at Close of Period, Land	[3]	10,374
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	43,988
Total		54,362
Accumulated depreciation	[2]	$ 19,632
Office [Member] | 140 East Ridgewood [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1981
Acquired		1997
Related Encumbrances		$ 11,720
Initial Costs, Land		7,932
Initial Costs, Building and Improvements		31,463
Costs Capitalized Subsequent to Acquisition		7,578
Gross Amount at Which Carried at Close of Period, Land	[3]	7,932
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	39,041
Total		46,973
Accumulated depreciation	[2]	$ 17,789
Office [Member] | 461 From Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		1997
Initial Costs, Land		$ 13,194
Initial Costs, Building and Improvements		52,778
Costs Capitalized Subsequent to Acquisition		10,587
Gross Amount at Which Carried at Close of Period, Land	[3]	13,194
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	63,365
Total		76,559
Accumulated depreciation	[2]	$ 24,838
Office [Member] | 650 From Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1978
Acquired		1997
Related Encumbrances		$ 22,484
Initial Costs, Land		10,487
Initial Costs, Building and Improvements		41,949
Costs Capitalized Subsequent to Acquisition		8,189
Gross Amount at Which Carried at Close of Period, Land	[3]	10,487
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	50,138
Total		60,625
Accumulated depreciation	[2]	$ 22,344
Office [Member] | 61 South Paramus Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1985
Acquired	[3]	1997
Related Encumbrances	[3]	$ 22,005
Initial Costs, Land	[3]	9,005
Initial Costs, Building and Improvements	[3]	36,018
Costs Capitalized Subsequent to Acquisition	[3]	9,162
Gross Amount at Which Carried at Close of Period, Land	[3]	9,005
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	45,180
Total	[3]	54,185
Accumulated depreciation	[2],[3]	$ 20,390
Office [Member] | 120 West Passaic Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1972
Acquired		1997
Initial Costs, Land		$ 1,354
Initial Costs, Building and Improvements		5,415
Costs Capitalized Subsequent to Acquisition		431
Gross Amount at Which Carried at Close of Period, Land	[3]	1,357
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	5,843
Total		7,200
Accumulated depreciation	[2]	$ 2,582
Office [Member] | 365 West Passaic Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1976
Acquired		1997
Related Encumbrances		$ 11,720
Initial Costs, Land		4,148
Initial Costs, Building and Improvements		16,592
Costs Capitalized Subsequent to Acquisition		5,497
Gross Amount at Which Carried at Close of Period, Land	[3]	4,148
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	22,089
Total		26,237
Accumulated depreciation	[2]	$ 9,804
Office [Member] | 395 West Passaic Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1979
Acquired		2006
Initial Costs, Land		$ 2,550
Initial Costs, Building and Improvements		17,131
Costs Capitalized Subsequent to Acquisition		1,020
Gross Amount at Which Carried at Close of Period, Land	[3]	2,550
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	18,151
Total		20,701
Accumulated depreciation	[2]	$ 4,324
Office [Member] | 1 Lake Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1994
Acquired		1997
Related Encumbrances		$ 40,184
Initial Costs, Land		13,952
Initial Costs, Building and Improvements		55,812
Costs Capitalized Subsequent to Acquisition		(37,797)
Gross Amount at Which Carried at Close of Period, Land	[3]	6,268
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	25,699
Total		31,967
Accumulated depreciation	[2]	$ 15,132
Office [Member] | 10 Mountainview Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1986
Acquired		1998
Initial Costs, Land		$ 4,240
Initial Costs, Building and Improvements		20,485
Costs Capitalized Subsequent to Acquisition		4,743
Gross Amount at Which Carried at Close of Period, Land	[3]	4,240
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	25,228
Total		29,468
Accumulated depreciation	[2]	$ 11,358
Office [Member] | 400 Chestnut Ridge Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1982
Acquired		1997
Initial Costs, Land		$ 4,201
Initial Costs, Building and Improvements		16,802
Costs Capitalized Subsequent to Acquisition		(6,770)
Gross Amount at Which Carried at Close of Period, Land	[3]	2,312
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	11,921
Total		14,233
Accumulated depreciation	[2]	$ 6,579
Office [Member] | 50 Tice Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1984
Acquired		1994
Related Encumbrances		$ 22,962
Initial Costs, Land		4,500
Costs Capitalized Subsequent to Acquisition		27,862
Gross Amount at Which Carried at Close of Period, Land	[3]	4,500
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	27,862
Total		32,362
Accumulated depreciation	[2]	$ 19,320
Office [Member] | 300 Tice Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1991
Acquired		1996
Initial Costs, Land		$ 5,424
Initial Costs, Building and Improvements		29,688
Costs Capitalized Subsequent to Acquisition		6,385
Gross Amount at Which Carried at Close of Period, Land	[3]	5,424
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	36,073
Total		41,497
Accumulated depreciation	[2]	$ 16,438
Office [Member] | 150 J.F. Kennedy Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1980
Acquired		1997
Initial Costs, Land		$ 12,606
Initial Costs, Building and Improvements		50,425
Costs Capitalized Subsequent to Acquisition		8,203
Gross Amount at Which Carried at Close of Period, Land	[1]	12,606
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	58,628
Total		71,234
Accumulated depreciation	[2]	$ 25,768
Office [Member] | 4 Becker Farm Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1983
Acquired		2009
Related Encumbrances		$ 40,083
Initial Costs, Land		5,600
Initial Costs, Building and Improvements		38,285
Costs Capitalized Subsequent to Acquisition		(9,089)
Gross Amount at Which Carried at Close of Period, Land	[1]	4,271
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	30,525
Total		34,796
Accumulated depreciation	[2]	$ 6,756
Office [Member] | 6 Becker Farm Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1983
Acquired		2009
Related Encumbrances		$ 13,829
Initial Costs, Land		2,600
Initial Costs, Building and Improvements		15,548
Costs Capitalized Subsequent to Acquisition		(7,006)
Gross Amount at Which Carried at Close of Period, Land	[1]	1,556
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	9,586
Total		11,142
Accumulated depreciation	[2]	$ 2,055
Office [Member] | 101 Eisenhower Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1980
Acquired		1994
Initial Costs, Land		$ 228
Costs Capitalized Subsequent to Acquisition		21,850
Gross Amount at Which Carried at Close of Period, Land	[1]	228
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	21,850
Total		22,078
Accumulated depreciation	[2]	$ 14,063
Office [Member] | 103 Eisenhower Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1985
Acquired		1994
Costs Capitalized Subsequent to Acquisition		$ 16,898
Gross Amount at Which Carried at Close of Period, Land	[1]	2,300
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	14,598
Total		16,898
Accumulated depreciation	[2]	$ 9,448
Office [Member] | 105 Eisenhower Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2001
Acquired		2001
Initial Costs, Land		$ 4,430
Initial Costs, Building and Improvements		42,898
Costs Capitalized Subsequent to Acquisition		5,670
Gross Amount at Which Carried at Close of Period, Land	[1]	3,835
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	49,163
Total		52,998
Accumulated depreciation	[2]	$ 22,616
Office [Member] | 75 Livingston Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1985
Acquired		2009
Related Encumbrances		$ 10,599
Initial Costs, Land		1,900
Initial Costs, Building and Improvements		6,312
Costs Capitalized Subsequent to Acquisition		(1,630)
Gross Amount at Which Carried at Close of Period, Land	[1]	1,281
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	5,301
Total		6,582
Accumulated depreciation	[2]	$ 1,206
Office [Member] | 85 Livingston Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1985
Acquired		2009
Related Encumbrances		$ 14,862
Initial Costs, Land		2,500
Initial Costs, Building and Improvements		14,238
Costs Capitalized Subsequent to Acquisition		(8,238)
Gross Amount at Which Carried at Close of Period, Land	[1]	1,234
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,266
Total		8,500
Accumulated depreciation	[2]	$ 1,622
Office [Member] | Harborside Plaza 1 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1983
Acquired		1996
Initial Costs, Land		$ 3,923
Initial Costs, Building and Improvements		51,013
Costs Capitalized Subsequent to Acquisition		27,985
Gross Amount at Which Carried at Close of Period, Land	[1]	3,923
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	78,998
Total		82,921
Accumulated depreciation	[2]	$ 39,183
Office [Member] | Harborside Plaza 2 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1996
Initial Costs, Land		$ 17,655
Initial Costs, Building and Improvements		101,546
Costs Capitalized Subsequent to Acquisition		25,245
Gross Amount at Which Carried at Close of Period, Land	[1]	12,844
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	131,602
Total		144,446
Accumulated depreciation	[2]	$ 58,486
Office [Member] | Harborside Plaza 3 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1996
Initial Costs, Land		$ 17,655
Initial Costs, Building and Improvements		101,878
Costs Capitalized Subsequent to Acquisition		24,911
Gross Amount at Which Carried at Close of Period, Land	[1]	12,843
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	131,601
Total		144,444
Accumulated depreciation	[2]	$ 58,486
Office [Member] | Harborside Plaza 4A [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2000
Acquired		2000
Initial Costs, Land		$ 1,244
Initial Costs, Building and Improvements		56,144
Costs Capitalized Subsequent to Acquisition		14,601
Gross Amount at Which Carried at Close of Period, Land	[1]	1,244
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	70,745
Total		71,989
Accumulated depreciation	[2]	$ 30,770
Office [Member] | Harborside Plaza 5 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2002
Acquired		2002
Related Encumbrances		$ 217,736
Initial Costs, Land		6,218
Initial Costs, Building and Improvements		170,682
Costs Capitalized Subsequent to Acquisition		56,368
Gross Amount at Which Carried at Close of Period, Land	[1]	5,705
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	227,563
Total		233,268
Accumulated depreciation	[2]	$ 86,807
Office [Member] | 101 Hudson Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1992
Acquired		2005
Initial Costs, Land		$ 45,530
Initial Costs, Building and Improvements		271,376
Costs Capitalized Subsequent to Acquisition		4,723
Gross Amount at Which Carried at Close of Period, Land	[1]	45,530
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	276,099
Total		321,629
Accumulated depreciation	[2]	$ 76,102
Office [Member] | 3 AAA Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1981
Acquired		2007
Initial Costs, Land		$ 242
Initial Costs, Building and Improvements		3,218
Costs Capitalized Subsequent to Acquisition		1,391
Gross Amount at Which Carried at Close of Period, Land	[1]	242
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,609
Total		4,851
Accumulated depreciation	[2]	$ 1,321
Office [Member] | 700 Horizon Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2007
Acquired		2007
Initial Costs, Land		$ 490
Initial Costs, Building and Improvements		43
Costs Capitalized Subsequent to Acquisition		16,663
Gross Amount at Which Carried at Close of Period, Land	[1]	865
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	16,331
Total		17,196
Accumulated depreciation	[2]	$ 4,028
Office [Member] | 2 South Gold Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1974
Acquired		2007
Initial Costs, Land		$ 476
Initial Costs, Building and Improvements		3,487
Costs Capitalized Subsequent to Acquisition		846
Gross Amount at Which Carried at Close of Period, Land	[1]	476
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,333
Total		4,809
Accumulated depreciation	[2]	$ 967
Office [Member] | 103 Carnegie Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1984
Acquired		1996
Initial Costs, Land		$ 2,566
Initial Costs, Building and Improvements		7,868
Costs Capitalized Subsequent to Acquisition		3,304
Gross Amount at Which Carried at Close of Period, Land	[1]	2,566
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	11,172
Total		13,738
Accumulated depreciation	[2]	$ 5,460
Office [Member] | 2 Independence Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1985
Acquired		2009
Initial Costs, Land		$ 1,300
Initial Costs, Building and Improvements		7,246
Costs Capitalized Subsequent to Acquisition		(4,079)
Gross Amount at Which Carried at Close of Period, Land	[1]	702
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,765
Total		4,467
Accumulated depreciation	[2]	$ 166
Office [Member] | 3 Independence Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1983
Acquired		1997
Initial Costs, Land		$ 1,997
Initial Costs, Building and Improvements		11,391
Costs Capitalized Subsequent to Acquisition		4,374
Gross Amount at Which Carried at Close of Period, Land	[1]	1,997
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	15,765
Total		17,762
Accumulated depreciation	[2]	$ 7,732
Office [Member] | 100 Overlook Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		1997
Initial Costs, Land		$ 2,378
Initial Costs, Building and Improvements		21,754
Costs Capitalized Subsequent to Acquisition		3,666
Gross Amount at Which Carried at Close of Period, Land	[1]	2,378
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	25,420
Total		27,798
Accumulated depreciation	[2]	$ 11,149
Office [Member] | 5 Vaughn Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1995
Initial Costs, Land		$ 657
Initial Costs, Building and Improvements		9,800
Costs Capitalized Subsequent to Acquisition		2,962
Gross Amount at Which Carried at Close of Period, Land	[1]	657
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	12,762
Total		13,419
Accumulated depreciation	[2]	$ 6,823
Office [Member] | 377 Summerhill Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1977
Acquired		1997
Initial Costs, Land		$ 649
Initial Costs, Building and Improvements		2,594
Costs Capitalized Subsequent to Acquisition		324
Gross Amount at Which Carried at Close of Period, Land	[1]	649
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,918
Total		3,567
Accumulated depreciation	[2]	$ 1,349
Office [Member] | 333 Thornall Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1984
Acquired		2015
Initial Costs, Land		$ 5,542
Initial Costs, Building and Improvements		40,762
Gross Amount at Which Carried at Close of Period, Land	[1]	5,542
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	40,762
Total		46,304
Accumulated depreciation	[2]	$ 247
Office [Member] | 343 Thornall Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1991
Acquired		2006
Initial Costs, Land		$ 6,027
Initial Costs, Building and Improvements		39,101
Costs Capitalized Subsequent to Acquisition		3,349
Gross Amount at Which Carried at Close of Period, Land	[1]	6,027
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	42,450
Total		48,477
Accumulated depreciation	[2]	$ 12,243
Office [Member] | 500 College Road East [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1984
Acquired	[3]	1998
Initial Costs, Land	[3]	$ 614
Initial Costs, Building and Improvements	[3]	20,626
Costs Capitalized Subsequent to Acquisition	[3]	4,839
Gross Amount at Which Carried at Close of Period, Land	[1],[3]	614
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1],[3]	25,465
Total	[3]	26,079
Accumulated depreciation	[2],[3]	$ 11,312
Office [Member] | 581 Main Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1991
Acquired		1997
Initial Costs, Land		$ 3,237
Initial Costs, Building and Improvements		12,949
Costs Capitalized Subsequent to Acquisition		26,135
Gross Amount at Which Carried at Close of Period, Land	[1]	8,115
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	34,206
Total		42,321
Accumulated depreciation	[2]	$ 16,730
Office [Member] | 2 Paragon Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1989
Acquired		2005
Initial Costs, Land		$ 999
Initial Costs, Building and Improvements		4,619
Costs Capitalized Subsequent to Acquisition		(864)
Gross Amount at Which Carried at Close of Period, Land	[1]	720
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,034
Total		4,754
Accumulated depreciation	[2]	$ 1,263
Office [Member] | 3 Paragon Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1991
Acquired		2005
Initial Costs, Land		$ 1,423
Initial Costs, Building and Improvements		6,041
Costs Capitalized Subsequent to Acquisition		(979)
Gross Amount at Which Carried at Close of Period, Land	[1]	1,020
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	5,465
Total		6,485
Accumulated depreciation	[2]	$ 1,809
Office [Member] | 4 Paragon Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2002
Acquired		2005
Initial Costs, Land		$ 1,961
Initial Costs, Building and Improvements		8,827
Costs Capitalized Subsequent to Acquisition		(3,107)
Gross Amount at Which Carried at Close of Period, Land	[1]	1,404
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	6,277
Total		7,681
Accumulated depreciation	[2]	$ 1,585
Office [Member] | 100 Willowbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		2005
Initial Costs, Land		$ 1,264
Initial Costs, Building and Improvements		5,573
Costs Capitalized Subsequent to Acquisition		(1,543)
Gross Amount at Which Carried at Close of Period, Land	[1]	869
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,425
Total		5,294
Accumulated depreciation	[2]	$ 1,442
Office [Member] | 23 Main Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1977
Acquired		2005
Related Encumbrances		$ 28,541
Initial Costs, Land		4,336
Initial Costs, Building and Improvements		19,544
Costs Capitalized Subsequent to Acquisition		9,133
Gross Amount at Which Carried at Close of Period, Land	[1]	4,336
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	28,677
Total		33,013
Accumulated depreciation	[2]	$ 12,775
Office [Member] | One River Center, Building 1 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1983
Acquired		2004
Related Encumbrances		$ 10,721
Initial Costs, Land		3,070
Initial Costs, Building and Improvements		17,414
Costs Capitalized Subsequent to Acquisition		4,065
Gross Amount at Which Carried at Close of Period, Land	[1]	2,451
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	22,098
Total		24,549
Accumulated depreciation	[2]	$ 7,840
Office [Member] | One River Center, Building 2 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1983
Acquired		2004
Related Encumbrances		$ 12,026
Initial Costs, Land		2,468
Initial Costs, Building and Improvements		15,043
Costs Capitalized Subsequent to Acquisition		3,894
Gross Amount at Which Carried at Close of Period, Land	[1]	2,452
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	18,953
Total		21,405
Accumulated depreciation	[2]	$ 5,441
Office [Member] | One River Center, Building 3 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1984
Acquired		2004
Related Encumbrances		$ 19,112
Initial Costs, Land		4,051
Initial Costs, Building and Improvements		24,790
Costs Capitalized Subsequent to Acquisition		6,171
Gross Amount at Which Carried at Close of Period, Land	[1]	4,627
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	30,385
Total		35,012
Accumulated depreciation	[2]	$ 9,435
Office [Member] | 3600 Route 66 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1989
Acquired		1995
Initial Costs, Land		$ 1,098
Initial Costs, Building and Improvements		18,146
Costs Capitalized Subsequent to Acquisition		11,397
Gross Amount at Which Carried at Close of Period, Land	[1]	1,098
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	29,543
Total		30,641
Accumulated depreciation	[2]	$ 11,448
Office [Member] | 1305 Campus Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		1995
Initial Costs, Land		$ 335
Initial Costs, Building and Improvements		2,560
Costs Capitalized Subsequent to Acquisition		707
Gross Amount at Which Carried at Close of Period, Land	[1]	291
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,311
Total		3,602
Accumulated depreciation	[2]	$ 1,618
Office [Member] | 1350 Campus Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1995
Initial Costs, Land		$ 454
Initial Costs, Building and Improvements		7,134
Costs Capitalized Subsequent to Acquisition		1,049
Gross Amount at Which Carried at Close of Period, Land	[1]	454
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	8,183
Total		8,637
Accumulated depreciation	[2]	$ 4,016
Office [Member] | 325 Columbia Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1994
Initial Costs, Land		$ 1,564
Costs Capitalized Subsequent to Acquisition		17,770
Gross Amount at Which Carried at Close of Period, Land	[1]	1,564
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	17,770
Total		19,334
Accumulated depreciation	[2]	$ 11,013
Office [Member] | 250 Johnson Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1977
Acquired		1997
Initial Costs, Land		$ 2,004
Initial Costs, Building and Improvements		8,016
Costs Capitalized Subsequent to Acquisition		(3,806)
Gross Amount at Which Carried at Close of Period, Land	[1]	930
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	5,284
Total		6,214
Accumulated depreciation	[2]	$ 4,265
Office [Member] | 201 Littleton Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1979
Acquired		1997
Initial Costs, Land		$ 2,407
Initial Costs, Building and Improvements		9,627
Costs Capitalized Subsequent to Acquisition		3,351
Gross Amount at Which Carried at Close of Period, Land	[1]	2,407
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	12,978
Total		15,385
Accumulated depreciation	[2]	$ 5,661
Office [Member] | 4 Campus Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1983
Acquired		2001
Initial Costs, Land		$ 5,213
Initial Costs, Building and Improvements		20,984
Costs Capitalized Subsequent to Acquisition		3,953
Gross Amount at Which Carried at Close of Period, Land	[1]	5,213
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	24,937
Total		30,150
Accumulated depreciation	[2]	$ 8,914
Office [Member] | 6 Campus Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1983
Acquired		2001
Initial Costs, Land		$ 4,411
Initial Costs, Building and Improvements		17,796
Costs Capitalized Subsequent to Acquisition		3,368
Gross Amount at Which Carried at Close of Period, Land	[1]	4,411
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	21,164
Total		25,575
Accumulated depreciation	[2]	$ 8,231
Office [Member] | 7 Campus Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1982
Acquired		1998
Initial Costs, Land		$ 1,932
Initial Costs, Building and Improvements		27,788
Costs Capitalized Subsequent to Acquisition		6,298
Gross Amount at Which Carried at Close of Period, Land	[1]	1,932
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	34,086
Total		36,018
Accumulated depreciation	[2]	$ 15,795
Office [Member] | 8 Campus Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1998
Initial Costs, Land		$ 1,865
Initial Costs, Building and Improvements		35,456
Costs Capitalized Subsequent to Acquisition		4,823
Gross Amount at Which Carried at Close of Period, Land	[1]	1,865
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	40,279
Total		42,144
Accumulated depreciation	[2]	$ 17,257
Office [Member] | 9 Campus Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1983
Acquired		2001
Initial Costs, Land		$ 3,277
Initial Costs, Building and Improvements		11,796
Costs Capitalized Subsequent to Acquisition		16,882
Gross Amount at Which Carried at Close of Period, Land	[1]	5,842
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	26,113
Total		31,955
Accumulated depreciation	[2]	$ 10,295
Office [Member] | 4 Century Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1981
Acquired		2004
Initial Costs, Land		$ 1,787
Initial Costs, Building and Improvements		9,575
Costs Capitalized Subsequent to Acquisition		(3,432)
Gross Amount at Which Carried at Close of Period, Land	[1]	1,086
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	6,844
Total		7,930
Accumulated depreciation	[2]	$ 2,188
Office [Member] | 5 Century Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1981
Acquired		2004
Initial Costs, Land		$ 1,762
Initial Costs, Building and Improvements		9,341
Costs Capitalized Subsequent to Acquisition		(3,796)
Gross Amount at Which Carried at Close of Period, Land	[1]	953
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	6,354
Total		7,307
Accumulated depreciation	[2]	$ 2,109
Office [Member] | 6 Century Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1981
Acquired		2004
Initial Costs, Land		$ 1,289
Initial Costs, Building and Improvements		6,848
Costs Capitalized Subsequent to Acquisition		(631)
Gross Amount at Which Carried at Close of Period, Land	[1]	990
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	6,516
Total		7,506
Accumulated depreciation	[2]	$ 1,966
Office [Member] | 2 Dryden Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1998
Initial Costs, Land		$ 778
Initial Costs, Building and Improvements		420
Costs Capitalized Subsequent to Acquisition		110
Gross Amount at Which Carried at Close of Period, Land	[1]	778
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	530
Total		1,308
Accumulated depreciation	[2]	$ 264
Office [Member] | 4 Gatehall Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		2000
Initial Costs, Land		$ 8,452
Initial Costs, Building and Improvements		33,929
Costs Capitalized Subsequent to Acquisition		4,055
Gross Amount at Which Carried at Close of Period, Land	[1]	8,452
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	37,984
Total		46,436
Accumulated depreciation	[2]	$ 15,223
Office [Member] | 2 Hilton Court [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1991
Acquired		1998
Initial Costs, Land		$ 1,971
Initial Costs, Building and Improvements		32,007
Costs Capitalized Subsequent to Acquisition		4,434
Gross Amount at Which Carried at Close of Period, Land	[1]	1,971
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	36,441
Total		38,412
Accumulated depreciation	[2]	$ 16,638
Office [Member] | 1633 Littleton Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1978
Acquired		2002
Initial Costs, Land		$ 2,283
Initial Costs, Building and Improvements		9,550
Costs Capitalized Subsequent to Acquisition		507
Gross Amount at Which Carried at Close of Period, Land	[1]	2,355
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	9,985
Total		12,340
Accumulated depreciation	[2]	$ 6,117
Office [Member] | 600 Parsippany Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1978
Acquired		1994
Initial Costs, Land		$ 1,257
Initial Costs, Building and Improvements		5,594
Costs Capitalized Subsequent to Acquisition		3,102
Gross Amount at Which Carried at Close of Period, Land	[1]	1,257
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	8,696
Total		9,953
Accumulated depreciation	[2]	$ 4,631
Office [Member] | 1 Sylvan Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1989
Acquired		1998
Initial Costs, Land		$ 1,689
Initial Costs, Building and Improvements		24,699
Costs Capitalized Subsequent to Acquisition		2,914
Gross Amount at Which Carried at Close of Period, Land	[1]	1,021
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	28,281
Total		29,302
Accumulated depreciation	[2]	$ 13,702
Office [Member] | 3 Sylvan Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		2015
Initial Costs, Land		$ 5,590
Initial Costs, Building and Improvements		4,710
Gross Amount at Which Carried at Close of Period, Land	[1]	5,590
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,710
Total		$ 10,300
Office [Member] | 5 Sylvan Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1989
Acquired		1998
Initial Costs, Land		$ 1,160
Initial Costs, Building and Improvements		25,214
Costs Capitalized Subsequent to Acquisition		2,866
Gross Amount at Which Carried at Close of Period, Land	[1]	1,161
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	28,079
Total		29,240
Accumulated depreciation	[2]	$ 12,067
Office [Member] | 7 Sylvan Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1998
Initial Costs, Land		$ 2,084
Initial Costs, Building and Improvements		26,083
Costs Capitalized Subsequent to Acquisition		1,185
Gross Amount at Which Carried at Close of Period, Land	[1]	2,084
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	27,268
Total		29,352
Accumulated depreciation	[2]	$ 11,760
Office [Member] | 20 Waterview Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		2009
Related Encumbrances		$ 23,989
Initial Costs, Land		4,500
Initial Costs, Building and Improvements		27,246
Costs Capitalized Subsequent to Acquisition		(4,222)
Gross Amount at Which Carried at Close of Period, Land	[1]	3,816
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	23,708
Total		27,524
Accumulated depreciation	[2]	$ 4,895
Office [Member] | 35 Waterview Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		2006
Initial Costs, Land		$ 5,133
Initial Costs, Building and Improvements		28,059
Costs Capitalized Subsequent to Acquisition		1,161
Gross Amount at Which Carried at Close of Period, Land	[1]	5,133
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	29,220
Total		34,353
Accumulated depreciation	[2]	$ 8,100
Office [Member] | 5 Wood Hollow Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1979
Acquired		2004
Initial Costs, Land		$ 5,302
Initial Costs, Building and Improvements		26,488
Costs Capitalized Subsequent to Acquisition		15,538
Gross Amount at Which Carried at Close of Period, Land	[1]	5,302
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	42,026
Total		47,328
Accumulated depreciation	[2]	$ 15,275
Office [Member] | 999 Riverview Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		1995
Initial Costs, Land		$ 476
Initial Costs, Building and Improvements		6,024
Costs Capitalized Subsequent to Acquisition		2,766
Gross Amount at Which Carried at Close of Period, Land	[1]	1,102
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	8,164
Total		9,266
Accumulated depreciation	[2]	$ 4,367
Office [Member] | 222 Mt. Airy Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1986
Acquired		1996
Initial Costs, Land		$ 775
Initial Costs, Building and Improvements		3,636
Costs Capitalized Subsequent to Acquisition		1,848
Gross Amount at Which Carried at Close of Period, Land	[1]	697
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	5,562
Total		6,259
Accumulated depreciation	[3]	$ 2,747
Office [Member] | 233 Mt. Airy Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1996
Initial Costs, Land		$ 1,034
Initial Costs, Building and Improvements		5,033
Costs Capitalized Subsequent to Acquisition		1,254
Gross Amount at Which Carried at Close of Period, Land	[1]	915
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	6,406
Total		7,321
Accumulated depreciation	[3]	$ 2,677
Office [Member] | 440 Route 22 East [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		2010
Initial Costs, Land		$ 3,986
Initial Costs, Building and Improvements		13,658
Costs Capitalized Subsequent to Acquisition		4,940
Gross Amount at Which Carried at Close of Period, Land	[1]	3,986
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	18,598
Total		22,584
Accumulated depreciation	[3]	$ 4,638
Office [Member] | 721 Route 202/206 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1989
Acquired		1997
Initial Costs, Land		$ 6,730
Initial Costs, Building and Improvements		26,919
Costs Capitalized Subsequent to Acquisition		(952)
Gross Amount at Which Carried at Close of Period, Land	[1]	5,067
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	27,630
Total		32,697
Accumulated depreciation	[3]	$ 14,895
Office [Member] | 100 Walnut Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1985
Acquired		1994
Related Encumbrances		$ 18,273
Costs Capitalized Subsequent to Acquisition		17,801
Gross Amount at Which Carried at Close of Period, Land	[1]	1,822
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	15,979
Total		17,801
Accumulated depreciation	[3]	$ 10,958
Office [Member] | 6 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1973
Acquired		1994
Initial Costs, Land		$ 250
Costs Capitalized Subsequent to Acquisition		1,728
Gross Amount at Which Carried at Close of Period, Land	[1]	250
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	1,728
Total		1,978
Accumulated depreciation	[3]	$ 704
Office [Member] | 11 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1981
Acquired		1994
Initial Costs, Land		$ 470
Costs Capitalized Subsequent to Acquisition		5,490
Gross Amount at Which Carried at Close of Period, Land	[1]	470
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	5,490
Total		5,960
Accumulated depreciation	[3]	$ 4,644
Office [Member] | 12 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1967
Acquired		1997
Initial Costs, Land		$ 887
Initial Costs, Building and Improvements		3,549
Costs Capitalized Subsequent to Acquisition		1,543
Gross Amount at Which Carried at Close of Period, Land	[1]	887
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	5,092
Total		5,979
Accumulated depreciation	[3]	$ 2,566
Office [Member] | 14 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1971
Acquired		2003
Initial Costs, Land		$ 1,283
Initial Costs, Building and Improvements		6,344
Costs Capitalized Subsequent to Acquisition		1,613
Gross Amount at Which Carried at Close of Period, Land	[1]	1,283
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,957
Total		9,240
Accumulated depreciation	[3]	$ 2,477
Office [Member] | 20 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1994
Initial Costs, Land		$ 2,346
Costs Capitalized Subsequent to Acquisition		21,663
Gross Amount at Which Carried at Close of Period, Land	[1]	2,346
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	21,663
Total		24,009
Accumulated depreciation	[3]	$ 11,901
Office [Member] | 25 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1971
Acquired		2002
Initial Costs, Land		$ 1,520
Initial Costs, Building and Improvements		6,186
Costs Capitalized Subsequent to Acquisition		864
Gross Amount at Which Carried at Close of Period, Land	[1]	1,520
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,050
Total		8,570
Accumulated depreciation	[3]	$ 3,239
Office [Member] | 65 Jackson Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1984
Acquired		1994
Initial Costs, Land		$ 541
Costs Capitalized Subsequent to Acquisition		6,377
Gross Amount at Which Carried at Close of Period, Land	[1]	542
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	6,376
Total		6,918
Accumulated depreciation	[3]	$ 4,381
Office [Member] | 890 Mountain Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1977
Acquired		1997
Initial Costs, Land		$ 2,796
Initial Costs, Building and Improvements		11,185
Costs Capitalized Subsequent to Acquisition		(4,798)
Gross Amount at Which Carried at Close of Period, Land	[1]	1,719
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,464
Total		9,183
Accumulated depreciation	[3]	$ 3,212
Office [Member] | 125 Broad Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1970
Acquired		2007
Initial Costs, Land		$ 50,191
Initial Costs, Building and Improvements		207,002
Costs Capitalized Subsequent to Acquisition		(48,039)
Gross Amount at Which Carried at Close of Period, Land	[1]	33,829
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	175,325
Total		209,154
Accumulated depreciation	[3]	$ 37,852
Office [Member] | 100 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1975
Acquired		1997
Initial Costs, Land		$ 220
Initial Costs, Building and Improvements		5,366
Costs Capitalized Subsequent to Acquisition		1,617
Gross Amount at Which Carried at Close of Period, Land	[1]	220
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	6,983
Total		7,203
Accumulated depreciation	[3]	$ 3,352
Office [Member] | 101 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1971
Acquired		1997
Initial Costs, Land		$ 267
Initial Costs, Building and Improvements		5,838
Costs Capitalized Subsequent to Acquisition		(3,528)
Gross Amount at Which Carried at Close of Period, Land	[1]	101
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,476
Total		2,577
Accumulated depreciation	[3]	$ 2,468
Office [Member] | 1 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1980
Acquired		1997
Initial Costs, Land		$ 66
Initial Costs, Building and Improvements		1,711
Costs Capitalized Subsequent to Acquisition		210
Gross Amount at Which Carried at Close of Period, Land	[1]	66
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	1,921
Total		1,987
Accumulated depreciation	[2]	$ 943
Office [Member] | 2 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1997
Initial Costs, Land		$ 109
Initial Costs, Building and Improvements		3,128
Costs Capitalized Subsequent to Acquisition		1,474
Gross Amount at Which Carried at Close of Period, Land	[1]	109
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,602
Total		4,711
Accumulated depreciation	[2]	$ 2,270
Office [Member] | 7 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1998
Initial Costs, Land		$ 330
Initial Costs, Building and Improvements		13,013
Costs Capitalized Subsequent to Acquisition		2,564
Gross Amount at Which Carried at Close of Period, Land	[1]	330
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	15,577
Total		15,907
Accumulated depreciation	[2]	$ 6,690
Office [Member] | 17 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1989
Acquired	[3]	1997
Initial Costs, Building and Improvements	[3]	$ 7,269
Costs Capitalized Subsequent to Acquisition	[3]	1,484
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1],[3]	8,753
Total	[3]	8,753
Accumulated depreciation	[2],[3]	$ 3,998
Office [Member] | 1 Barker Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1975
Acquired		1997
Initial Costs, Land		$ 208
Initial Costs, Building and Improvements		9,629
Costs Capitalized Subsequent to Acquisition		2,590
Gross Amount at Which Carried at Close of Period, Land	[1]	207
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	12,220
Total		12,427
Accumulated depreciation	[2]	$ 5,489
Office [Member] | 3 Barker Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1983
Acquired		1997
Initial Costs, Land		$ 122
Initial Costs, Building and Improvements		7,864
Costs Capitalized Subsequent to Acquisition		1,848
Gross Amount at Which Carried at Close of Period, Land	[1]	122
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	9,712
Total		9,834
Accumulated depreciation	[2]	$ 4,473
Office [Member] | 50 Main Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1985
Acquired		1997
Initial Costs, Land		$ 564
Initial Costs, Building and Improvements		48,105
Costs Capitalized Subsequent to Acquisition		14,554
Gross Amount at Which Carried at Close of Period, Land	[1]	564
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	62,659
Total		63,223
Accumulated depreciation	[2]	$ 29,323
Office [Member] | 11 Martine Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1997
Initial Costs, Land		$ 127
Initial Costs, Building and Improvements		26,833
Costs Capitalized Subsequent to Acquisition		8,561
Gross Amount at Which Carried at Close of Period, Land	[1]	127
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	35,394
Total		35,521
Accumulated depreciation	[2]	$ 16,002
Office [Member] | 1 Water Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1979
Acquired		1997
Initial Costs, Land		$ 211
Initial Costs, Building and Improvements		5,382
Costs Capitalized Subsequent to Acquisition		1,341
Gross Amount at Which Carried at Close of Period, Land	[1]	211
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	6,723
Total		6,934
Accumulated depreciation	[2]	$ 3,043
Office [Member] | 1 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1982
Acquired		1997
Initial Costs, Land		$ 1,104
Initial Costs, Building and Improvements		11,904
Costs Capitalized Subsequent to Acquisition		2,998
Gross Amount at Which Carried at Close of Period, Land	[1]	1,105
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	14,901
Total		16,006
Accumulated depreciation	[2]	$ 6,732
Office [Member] | 3 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1997
Initial Costs, Land		$ 385
Initial Costs, Building and Improvements		6,256
Costs Capitalized Subsequent to Acquisition		1,772
Gross Amount at Which Carried at Close of Period, Land	[1]	385
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	8,028
Total		8,413
Accumulated depreciation	[2]	$ 3,625
Office [Member] | 3 Odell Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1984
Acquired		2003
Initial Costs, Land		$ 1,322
Initial Costs, Building and Improvements		4,777
Costs Capitalized Subsequent to Acquisition		2,332
Gross Amount at Which Carried at Close of Period, Land	[1]	1,322
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,109
Total		8,431
Accumulated depreciation	[2]	$ 3,259
Office [Member] | 1201 Connecticut Avenue, NW [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1940
Acquired		1999
Initial Costs, Land		$ 14,228
Initial Costs, Building and Improvements		18,571
Costs Capitalized Subsequent to Acquisition		6,895
Gross Amount at Which Carried at Close of Period, Land	[1]	14,228
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	25,466
Total		39,694
Accumulated depreciation	[2]	$ 11,390
Office [Member] | 1400 L Street, NW [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1998
Initial Costs, Land		$ 13,054
Initial Costs, Building and Improvements		27,423
Costs Capitalized Subsequent to Acquisition		7,910
Gross Amount at Which Carried at Close of Period, Land	[1]	13,054
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	35,333
Total		48,387
Accumulated depreciation	[2]	$ 18,841
Office [Member] | 9200 Edmonston Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired		2006
Related Encumbrances		$ 3,793
Initial Costs, Land		1,547
Initial Costs, Building and Improvements		4,131
Costs Capitalized Subsequent to Acquisition		(2,484)
Gross Amount at Which Carried at Close of Period, Land	[1]	610
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,584
Total		3,194
Accumulated depreciation	[2]	$ 1,376
Office [Member] | 6301 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired		2006
Initial Costs, Land		$ 5,168
Initial Costs, Building and Improvements		14,706
Costs Capitalized Subsequent to Acquisition		(9,924)
Gross Amount at Which Carried at Close of Period, Land	[1]	2,431
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,519
Total		9,950
Accumulated depreciation	[2]	$ 1,988
Office [Member] | 6303 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired		2006
Initial Costs, Land		$ 5,115
Initial Costs, Building and Improvements		13,860
Costs Capitalized Subsequent to Acquisition		(10,097)
Gross Amount at Which Carried at Close of Period, Land	[1]	2,436
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	6,442
Total		8,878
Accumulated depreciation	[2]	$ 1,584
Office [Member] | 6305 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired		2006
Initial Costs, Land		$ 5,615
Initial Costs, Building and Improvements		14,420
Costs Capitalized Subsequent to Acquisition		(10,137)
Gross Amount at Which Carried at Close of Period, Land	[1]	2,599
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,299
Total		9,898
Accumulated depreciation	[2]	$ 1,972
Office [Member] | 6404 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		2006
Initial Costs, Land		$ 7,578
Initial Costs, Building and Improvements		20,785
Costs Capitalized Subsequent to Acquisition		(14,343)
Gross Amount at Which Carried at Close of Period, Land	[1]	3,437
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	10,583
Total		14,020
Accumulated depreciation	[2]	$ 3,376
Office [Member] | 6406 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1991
Acquired		2006
Initial Costs, Land		$ 7,514
Initial Costs, Building and Improvements		21,152
Costs Capitalized Subsequent to Acquisition		(14,034)
Gross Amount at Which Carried at Close of Period, Land	[1]	3,158
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	11,474
Total		14,632
Accumulated depreciation	[2]	$ 2,570
Office [Member] | 6411 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired		2006
Initial Costs, Land		$ 6,867
Initial Costs, Building and Improvements		17,470
Costs Capitalized Subsequent to Acquisition		(12,445)
Gross Amount at Which Carried at Close of Period, Land	[1]	3,216
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	8,676
Total		11,892
Accumulated depreciation	[2]	$ 2,452
Office [Member] | 4200 Parliament Place [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1989
Acquired		1998
Initial Costs, Land		$ 2,114
Initial Costs, Building and Improvements		13,546
Costs Capitalized Subsequent to Acquisition		(6,173)
Gross Amount at Which Carried at Close of Period, Land	[1]	774
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	8,713
Total		9,487
Accumulated depreciation	[2]	$ 4,258
Office And Office/Flex Buildings [Member] | 3 Terri Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1991
Acquired		1998
Initial Costs, Land		$ 652
Initial Costs, Building and Improvements		3,433
Costs Capitalized Subsequent to Acquisition		1,549
Gross Amount at Which Carried at Close of Period, Land	[3]	658
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	4,976
Total		5,634
Accumulated depreciation	[2]	$ 2,285
Office And Office/Flex Buildings [Member] | 5 Terri Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1992
Acquired		1998
Initial Costs, Land		$ 564
Initial Costs, Building and Improvements		3,792
Costs Capitalized Subsequent to Acquisition		2,272
Gross Amount at Which Carried at Close of Period, Land	[3]	569
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	6,059
Total		6,628
Accumulated depreciation	[2]	$ 2,856
Office And Office/Flex Buildings [Member] | 2 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1986
Acquired		1999
Initial Costs, Land		$ 723
Initial Costs, Building and Improvements		2,893
Costs Capitalized Subsequent to Acquisition		544
Gross Amount at Which Carried at Close of Period, Land	[3]	723
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	3,437
Total		4,160
Accumulated depreciation	[2]	$ 1,461
Office And Office/Flex Buildings [Member] | 101 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		1998
Initial Costs, Land		$ 422
Initial Costs, Building and Improvements		3,528
Costs Capitalized Subsequent to Acquisition		436
Gross Amount at Which Carried at Close of Period, Land	[3]	426
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	3,960
Total		4,386
Accumulated depreciation	[2]	$ 1,893
Office And Office/Flex Buildings [Member] | 102 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1999
Initial Costs, Land		$ 389
Initial Costs, Building and Improvements		1,554
Costs Capitalized Subsequent to Acquisition		482
Gross Amount at Which Carried at Close of Period, Land	[3]	389
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	2,036
Total		2,425
Accumulated depreciation	[2]	$ 732
Office And Office/Flex Buildings [Member] | 201 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1986
Acquired		1998
Initial Costs, Land		$ 254
Initial Costs, Building and Improvements		1,694
Costs Capitalized Subsequent to Acquisition		349
Gross Amount at Which Carried at Close of Period, Land	[3]	258
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	2,039
Total		2,297
Accumulated depreciation	[2]	$ 922
Office And Office/Flex Buildings [Member] | 202 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		1999
Initial Costs, Land		$ 490
Initial Costs, Building and Improvements		1,963
Costs Capitalized Subsequent to Acquisition		384
Gross Amount at Which Carried at Close of Period, Land	[3]	490
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	2,347
Total		2,837
Accumulated depreciation	[2]	$ 919
Office And Office/Flex Buildings [Member] | 1 Executive Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1989
Acquired		1998
Initial Costs, Land		$ 226
Initial Costs, Building and Improvements		1,453
Costs Capitalized Subsequent to Acquisition		772
Gross Amount at Which Carried at Close of Period, Land	[3]	228
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	2,223
Total		2,451
Accumulated depreciation	[2]	$ 979
Office And Office/Flex Buildings [Member] | 2 Executive Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		2000
Initial Costs, Land		$ 801
Initial Costs, Building and Improvements		3,206
Costs Capitalized Subsequent to Acquisition		980
Gross Amount at Which Carried at Close of Period, Land	[3]	801
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	4,186
Total		4,987
Accumulated depreciation	[2]	$ 1,530
Office And Office/Flex Buildings [Member] | 101 Executive Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1998
Initial Costs, Land		$ 241
Initial Costs, Building and Improvements		2,262
Costs Capitalized Subsequent to Acquisition		701
Gross Amount at Which Carried at Close of Period, Land	[3]	244
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	2,960
Total		3,204
Accumulated depreciation	[2]	$ 1,328
Office And Office/Flex Buildings [Member] | 102 Executive Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1998
Initial Costs, Land		$ 353
Initial Costs, Building and Improvements		3,607
Costs Capitalized Subsequent to Acquisition		420
Gross Amount at Which Carried at Close of Period, Land	[3]	357
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	4,023
Total		4,380
Accumulated depreciation	[2]	$ 1,812
Office And Office/Flex Buildings [Member] | 225 Executive Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1998
Initial Costs, Land		$ 323
Initial Costs, Building and Improvements		2,477
Costs Capitalized Subsequent to Acquisition		457
Gross Amount at Which Carried at Close of Period, Land	[3]	326
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	2,931
Total		3,257
Accumulated depreciation	[2]	$ 1,280
Office And Office/Flex Buildings [Member] | 97 Foster Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1982
Acquired		1998
Initial Costs, Land		$ 208
Initial Costs, Building and Improvements		1,382
Costs Capitalized Subsequent to Acquisition		389
Gross Amount at Which Carried at Close of Period, Land	[3]	211
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	1,768
Total		1,979
Accumulated depreciation	[2]	$ 885
Office And Office/Flex Buildings [Member] | 1507 Lancer Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1995
Acquired		1998
Initial Costs, Land		$ 119
Initial Costs, Building and Improvements		1,106
Costs Capitalized Subsequent to Acquisition		209
Gross Amount at Which Carried at Close of Period, Land	[3]	120
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	1,314
Total		1,434
Accumulated depreciation	[2]	$ 612
Office And Office/Flex Buildings [Member] | 1245 North Church Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1998
Acquired		2001
Initial Costs, Land		$ 691
Initial Costs, Building and Improvements		2,810
Costs Capitalized Subsequent to Acquisition		110
Gross Amount at Which Carried at Close of Period, Land	[3]	691
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	2,920
Total		3,611
Accumulated depreciation	[2]	$ 1,078
Office And Office/Flex Buildings [Member] | 1247 North Church Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1998
Acquired		2001
Initial Costs, Land		$ 805
Initial Costs, Building and Improvements		3,269
Costs Capitalized Subsequent to Acquisition		175
Gross Amount at Which Carried at Close of Period, Land	[3]	805
Gross Amount at Which Carried at Close of Period, Building and Improvements	[3]	3,444
Total		4,249
Accumulated depreciation	[2]	$ 1,287
Office And Office/Flex Buildings [Member] | 1256 North Church Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1984
Acquired		1998
Initial Costs, Land		$ 354
Initial Costs, Building and Improvements		3,098
Costs Capitalized Subsequent to Acquisition		658
Gross Amount at Which Carried at Close of Period, Land	[1]	357
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,753
Total		4,110
Accumulated depreciation	[2]	$ 1,678
Office And Office/Flex Buildings [Member] | 840 North Lenola Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1995
Acquired		1998
Initial Costs, Land		$ 329
Initial Costs, Building and Improvements		2,366
Costs Capitalized Subsequent to Acquisition		499
Gross Amount at Which Carried at Close of Period, Land	[1]	333
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,861
Total		3,194
Accumulated depreciation	[2]	$ 1,286
Office And Office/Flex Buildings [Member] | 844 North Lenola Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1995
Acquired		1998
Initial Costs, Land		$ 239
Initial Costs, Building and Improvements		1,714
Costs Capitalized Subsequent to Acquisition		298
Gross Amount at Which Carried at Close of Period, Land	[1]	241
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,010
Total		2,251
Accumulated depreciation	[2]	$ 957
Office And Office/Flex Buildings [Member] | 915 North Lenola Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1998
Acquired		2000
Initial Costs, Land		$ 508
Initial Costs, Building and Improvements		2,034
Costs Capitalized Subsequent to Acquisition		215
Gross Amount at Which Carried at Close of Period, Land	[1]	508
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,249
Total		2,757
Accumulated depreciation	[2]	$ 985
Office And Office/Flex Buildings [Member] | 2 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2000
Acquired		2001
Initial Costs, Land		$ 701
Initial Costs, Building and Improvements		2,807
Costs Capitalized Subsequent to Acquisition		225
Gross Amount at Which Carried at Close of Period, Land	[1]	701
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,032
Total		3,733
Accumulated depreciation	[2]	$ 1,077
Office And Office/Flex Buildings [Member] | 30 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1997
Acquired		1998
Initial Costs, Land		$ 234
Initial Costs, Building and Improvements		1,954
Costs Capitalized Subsequent to Acquisition		510
Gross Amount at Which Carried at Close of Period, Land	[1]	236
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,462
Total		2,698
Accumulated depreciation	[2]	$ 1,251
Office And Office/Flex Buildings [Member] | 31 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1998
Acquired		2001
Initial Costs, Land		$ 815
Initial Costs, Building and Improvements		3,276
Costs Capitalized Subsequent to Acquisition		258
Gross Amount at Which Carried at Close of Period, Land	[1]	815
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,534
Total		4,349
Accumulated depreciation	[2]	$ 1,303
Office And Office/Flex Buildings [Member] | 40 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1996
Acquired		1998
Initial Costs, Land		$ 297
Initial Costs, Building and Improvements		2,393
Costs Capitalized Subsequent to Acquisition		160
Gross Amount at Which Carried at Close of Period, Land	[1]	301
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,549
Total		2,850
Accumulated depreciation	[2]	$ 1,180
Office And Office/Flex Buildings [Member] | 41 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1998
Acquired		2001
Initial Costs, Land		$ 605
Initial Costs, Building and Improvements		2,459
Costs Capitalized Subsequent to Acquisition		214
Gross Amount at Which Carried at Close of Period, Land	[1]	605
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,673
Total		3,278
Accumulated depreciation	[2]	$ 1,016
Office And Office/Flex Buildings [Member] | 50 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1997
Acquired		1998
Initial Costs, Land		$ 301
Initial Costs, Building and Improvements		2,330
Costs Capitalized Subsequent to Acquisition		98
Gross Amount at Which Carried at Close of Period, Land	[1]	304
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,425
Total		2,729
Accumulated depreciation	[2]	$ 1,133
Office And Office/Flex Buildings [Member] | 100 Horizon Center Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1989
Acquired		1995
Initial Costs, Land		$ 205
Initial Costs, Building and Improvements		1,676
Costs Capitalized Subsequent to Acquisition		730
Gross Amount at Which Carried at Close of Period, Land	[1]	325
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,286
Total		2,611
Accumulated depreciation	[2]	$ 1,029
Office And Office/Flex Buildings [Member] | 200 Horizon Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1991
Acquired		1995
Initial Costs, Land		$ 205
Initial Costs, Building and Improvements		3,027
Costs Capitalized Subsequent to Acquisition		715
Gross Amount at Which Carried at Close of Period, Land	[1]	357
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,590
Total		3,947
Accumulated depreciation	[2]	$ 1,845
Office And Office/Flex Buildings [Member] | 300 Horizon Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1989
Acquired		1995
Initial Costs, Land		$ 379
Initial Costs, Building and Improvements		4,355
Costs Capitalized Subsequent to Acquisition		1,428
Gross Amount at Which Carried at Close of Period, Land	[1]	531
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	5,631
Total		6,162
Accumulated depreciation	[2]	$ 2,641
Office And Office/Flex Buildings [Member] | 500 Horizon Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1995
Initial Costs, Land		$ 379
Initial Costs, Building and Improvements		3,395
Costs Capitalized Subsequent to Acquisition		901
Gross Amount at Which Carried at Close of Period, Land	[1]	496
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,179
Total		4,675
Accumulated depreciation	[2]	$ 2,152
Office And Office/Flex Buildings [Member] | 600 Horizon Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2002
Acquired		2002
Initial Costs, Building and Improvements		$ 7,549
Costs Capitalized Subsequent to Acquisition		709
Gross Amount at Which Carried at Close of Period, Land	[1]	685
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,573
Total		8,258
Accumulated depreciation	[2]	$ 2,478
Office And Office/Flex Buildings [Member] | 1325 Campus Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		1995
Initial Costs, Land		$ 270
Initial Costs, Building and Improvements		2,928
Costs Capitalized Subsequent to Acquisition		725
Gross Amount at Which Carried at Close of Period, Land	[1]	270
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,653
Total		3,923
Accumulated depreciation	[2]	$ 1,914
Office And Office/Flex Buildings [Member] | 1340 Campus Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1992
Acquired		1995
Initial Costs, Land		$ 489
Initial Costs, Building and Improvements		4,621
Costs Capitalized Subsequent to Acquisition		1,836
Gross Amount at Which Carried at Close of Period, Land	[1]	489
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	6,457
Total		6,946
Accumulated depreciation	[2]	$ 3,434
Office And Office/Flex Buildings [Member] | 1345 Campus Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1995
Acquired		1997
Initial Costs, Land		$ 1,023
Initial Costs, Building and Improvements		5,703
Costs Capitalized Subsequent to Acquisition		1,772
Gross Amount at Which Carried at Close of Period, Land	[1]	1,024
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,474
Total		8,498
Accumulated depreciation	[2]	$ 3,841
Office And Office/Flex Buildings [Member] | 1433 Highway 34 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1985
Acquired		1995
Initial Costs, Land		$ 889
Initial Costs, Building and Improvements		4,321
Costs Capitalized Subsequent to Acquisition		1,655
Gross Amount at Which Carried at Close of Period, Land	[1]	889
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	5,976
Total		6,865
Accumulated depreciation	[2]	$ 2,972
Office And Office/Flex Buildings [Member] | 1320 Wyckoff Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1986
Acquired		1995
Initial Costs, Land		$ 255
Initial Costs, Building and Improvements		1,285
Costs Capitalized Subsequent to Acquisition		291
Gross Amount at Which Carried at Close of Period, Land	[1]	216
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	1,615
Total		1,831
Accumulated depreciation	[2]	$ 908
Office And Office/Flex Buildings [Member] | 1324 Wyckoff Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1995
Initial Costs, Land		$ 230
Initial Costs, Building and Improvements		1,439
Costs Capitalized Subsequent to Acquisition		317
Gross Amount at Which Carried at Close of Period, Land	[1]	190
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	1,796
Total		1,986
Accumulated depreciation	[2]	$ 853
Office And Office/Flex Buildings [Member] | 1 Center Court [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1999
Acquired		1999
Initial Costs, Land		$ 270
Initial Costs, Building and Improvements		1,824
Costs Capitalized Subsequent to Acquisition		490
Gross Amount at Which Carried at Close of Period, Land	[1]	270
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,314
Total		2,584
Accumulated depreciation	[2]	$ 990
Office And Office/Flex Buildings [Member] | 2 Center Court [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1998
Acquired		1998
Initial Costs, Land		$ 191
Costs Capitalized Subsequent to Acquisition		2,476
Gross Amount at Which Carried at Close of Period, Land	[1]	191
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,476
Total		2,667
Accumulated depreciation	[2]	$ 1,089
Office And Office/Flex Buildings [Member] | 11 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1989
Acquired		1995
Initial Costs, Land		$ 586
Initial Costs, Building and Improvements		2,986
Costs Capitalized Subsequent to Acquisition		1,000
Gross Amount at Which Carried at Close of Period, Land	[1]	586
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,986
Total		4,572
Accumulated depreciation	[2]	$ 2,086
Office And Office/Flex Buildings [Member] | 20 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1992
Acquired		1995
Initial Costs, Land		$ 516
Initial Costs, Building and Improvements		3,108
Costs Capitalized Subsequent to Acquisition		111
Gross Amount at Which Carried at Close of Period, Land	[1]	516
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,219
Total		3,735
Accumulated depreciation	[2]	$ 1,600
Office And Office/Flex Buildings [Member] | 29 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1995
Initial Costs, Land		$ 586
Initial Costs, Building and Improvements		3,092
Costs Capitalized Subsequent to Acquisition		961
Gross Amount at Which Carried at Close of Period, Land	[1]	586
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,053
Total		4,639
Accumulated depreciation	[2]	$ 1,809
Office And Office/Flex Buildings [Member] | 40 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1995
Initial Costs, Land		$ 516
Initial Costs, Building and Improvements		3,260
Costs Capitalized Subsequent to Acquisition		1,509
Gross Amount at Which Carried at Close of Period, Land	[1]	516
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,769
Total		5,285
Accumulated depreciation	[2]	$ 2,293
Office And Office/Flex Buildings [Member] | 45 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1992
Acquired		1995
Initial Costs, Land		$ 536
Initial Costs, Building and Improvements		3,379
Costs Capitalized Subsequent to Acquisition		497
Gross Amount at Which Carried at Close of Period, Land	[1]	536
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,876
Total		4,412
Accumulated depreciation	[2]	$ 1,940
Office And Office/Flex Buildings [Member] | 60 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		1995
Initial Costs, Land		$ 526
Initial Costs, Building and Improvements		3,257
Costs Capitalized Subsequent to Acquisition		507
Gross Amount at Which Carried at Close of Period, Land	[1]	526
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,764
Total		4,290
Accumulated depreciation	[2]	$ 2,048
Office And Office/Flex Buildings [Member] | 80 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1996
Acquired		1996
Initial Costs, Land		$ 227
Costs Capitalized Subsequent to Acquisition		1,348
Gross Amount at Which Carried at Close of Period, Land	[1]	227
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	1,348
Total		1,575
Accumulated depreciation	[2]	$ 638
Office And Office/Flex Buildings [Member] | 100 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1996
Acquired		1996
Initial Costs, Land		$ 226
Costs Capitalized Subsequent to Acquisition		1,348
Gross Amount at Which Carried at Close of Period, Land	[1]	226
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	1,348
Total		1,574
Accumulated depreciation	[2]	$ 637
Office And Office/Flex Buildings [Member] | 120 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1994
Acquired		1995
Initial Costs, Land		$ 228
Costs Capitalized Subsequent to Acquisition		1,284
Gross Amount at Which Carried at Close of Period, Land	[1]	229
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	1,283
Total		1,512
Accumulated depreciation	[2]	$ 657
Office And Office/Flex Buildings [Member] | 140 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1994
Acquired		1995
Initial Costs, Land		$ 229
Costs Capitalized Subsequent to Acquisition		1,282
Gross Amount at Which Carried at Close of Period, Land	[1]	228
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	1,283
Total		1,511
Accumulated depreciation	[2]	$ 657
Office And Office/Flex Buildings [Member] | 11 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1974
Acquired		1997
Initial Costs, Land		$ 149
Initial Costs, Building and Improvements		2,159
Costs Capitalized Subsequent to Acquisition		602
Gross Amount at Which Carried at Close of Period, Land	[1]	149
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,761
Total		2,910
Accumulated depreciation	[3]	$ 1,278
Office And Office/Flex Buildings [Member] | 75 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1997
Initial Costs, Land		$ 2,314
Initial Costs, Building and Improvements		4,716
Costs Capitalized Subsequent to Acquisition		57
Gross Amount at Which Carried at Close of Period, Land	[1]	2,314
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,773
Total		7,087
Accumulated depreciation	[3]	$ 2,259
Office And Office/Flex Buildings [Member] | 125 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2002
Acquired		2002
Initial Costs, Land		$ 1,055
Initial Costs, Building and Improvements		3,676
Costs Capitalized Subsequent to Acquisition		(445)
Gross Amount at Which Carried at Close of Period, Land	[1]	1,055
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,231
Total		4,286
Accumulated depreciation	[3]	$ 1,145
Office And Office/Flex Buildings [Member] | 150 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1975
Acquired		1997
Initial Costs, Land		$ 497
Initial Costs, Building and Improvements		7,030
Costs Capitalized Subsequent to Acquisition		2,221
Gross Amount at Which Carried at Close of Period, Land	[1]	497
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	9,251
Total		9,748
Accumulated depreciation	[3]	$ 4,104
Office And Office/Flex Buildings [Member] | 175 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1973
Acquired		1997
Initial Costs, Land		$ 655
Initial Costs, Building and Improvements		7,473
Costs Capitalized Subsequent to Acquisition		762
Gross Amount at Which Carried at Close of Period, Land	[1]	655
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	8,235
Total		8,890
Accumulated depreciation	[3]	$ 3,863
Office And Office/Flex Buildings [Member] | 200 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1974
Acquired		1997
Initial Costs, Land		$ 579
Initial Costs, Building and Improvements		6,620
Costs Capitalized Subsequent to Acquisition		1,888
Gross Amount at Which Carried at Close of Period, Land	[1]	579
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	8,508
Total		9,087
Accumulated depreciation	[3]	$ 3,852
Office And Office/Flex Buildings [Member] | 250 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1973
Acquired		1997
Initial Costs, Land		$ 867
Initial Costs, Building and Improvements		8,647
Costs Capitalized Subsequent to Acquisition		2,395
Gross Amount at Which Carried at Close of Period, Land	[1]	867
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	11,042
Total		11,909
Accumulated depreciation	[3]	$ 4,697
Office And Office/Flex Buildings [Member] | 50 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1969
Acquired		1997
Initial Costs, Land		$ 237
Initial Costs, Building and Improvements		2,617
Costs Capitalized Subsequent to Acquisition		441
Gross Amount at Which Carried at Close of Period, Land	[1]	237
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,058
Total		3,295
Accumulated depreciation	[3]	$ 1,404
Office And Office/Flex Buildings [Member] | 77 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1977
Acquired		1997
Initial Costs, Land		$ 34
Initial Costs, Building and Improvements		1,104
Costs Capitalized Subsequent to Acquisition		212
Gross Amount at Which Carried at Close of Period, Land	[1]	34
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	1,316
Total		1,350
Accumulated depreciation	[3]	$ 677
Office And Office/Flex Buildings [Member] | 85 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1968
Acquired		1997
Initial Costs, Land		$ 155
Initial Costs, Building and Improvements		2,507
Costs Capitalized Subsequent to Acquisition		516
Gross Amount at Which Carried at Close of Period, Land	[1]	155
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,023
Total		3,178
Accumulated depreciation	[3]	$ 1,284
Office And Office/Flex Buildings [Member] | 300 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1970
Acquired		1997
Initial Costs, Land		$ 460
Initial Costs, Building and Improvements		3,609
Costs Capitalized Subsequent to Acquisition		306
Gross Amount at Which Carried at Close of Period, Land	[1]	460
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,915
Total		4,375
Accumulated depreciation	[3]	$ 1,802
Office And Office/Flex Buildings [Member] | 350 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1970
Acquired		1997
Initial Costs, Land		$ 100
Initial Costs, Building and Improvements		1,793
Costs Capitalized Subsequent to Acquisition		175
Gross Amount at Which Carried at Close of Period, Land	[1]	100
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	1,968
Total		2,068
Accumulated depreciation	[2]	$ 942
Office And Office/Flex Buildings [Member] | 399 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1962
Acquired		1997
Initial Costs, Land		$ 531
Initial Costs, Building and Improvements		7,191
Costs Capitalized Subsequent to Acquisition		163
Gross Amount at Which Carried at Close of Period, Land	[1]	531
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,354
Total		7,885
Accumulated depreciation	[2]	$ 3,502
Office And Office/Flex Buildings [Member] | 400 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1970
Acquired		1997
Initial Costs, Land		$ 2,202
Initial Costs, Building and Improvements		1,846
Costs Capitalized Subsequent to Acquisition		938
Gross Amount at Which Carried at Close of Period, Land	[1]	2,202
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,784
Total		4,986
Accumulated depreciation	[2]	$ 1,407
Office And Office/Flex Buildings [Member] | 500 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1970
Acquired		1997
Initial Costs, Land		$ 258
Initial Costs, Building and Improvements		4,183
Costs Capitalized Subsequent to Acquisition		434
Gross Amount at Which Carried at Close of Period, Land	[1]	258
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,617
Total		4,875
Accumulated depreciation	[2]	$ 2,268
Office And Office/Flex Buildings [Member] | 525 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1972
Acquired		1997
Initial Costs, Land		$ 345
Initial Costs, Building and Improvements		5,499
Costs Capitalized Subsequent to Acquisition		837
Gross Amount at Which Carried at Close of Period, Land	[1]	345
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	6,336
Total		6,681
Accumulated depreciation	[2]	$ 3,082
Office And Office/Flex Buildings [Member] | 1 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1967
Acquired		1997
Initial Costs, Land		$ 199
Initial Costs, Building and Improvements		2,023
Costs Capitalized Subsequent to Acquisition		469
Gross Amount at Which Carried at Close of Period, Land	[1]	199
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,492
Total		2,691
Accumulated depreciation	[2]	$ 1,318
Office And Office/Flex Buildings [Member] | 2 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1968
Acquired		1997
Initial Costs, Land		$ 234
Initial Costs, Building and Improvements		2,726
Costs Capitalized Subsequent to Acquisition		686
Gross Amount at Which Carried at Close of Period, Land	[1]	234
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,412
Total		3,646
Accumulated depreciation	[2]	$ 1,510
Office And Office/Flex Buildings [Member] | 3 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1969
Acquired		1997
Initial Costs, Land		$ 655
Initial Costs, Building and Improvements		7,936
Costs Capitalized Subsequent to Acquisition		1,343
Gross Amount at Which Carried at Close of Period, Land	[1]	655
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	9,279
Total		9,934
Accumulated depreciation	[2]	$ 4,453
Office And Office/Flex Buildings [Member] | 4 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1969
Acquired		1997
Initial Costs, Land		$ 320
Initial Costs, Building and Improvements		3,729
Costs Capitalized Subsequent to Acquisition		1,244
Gross Amount at Which Carried at Close of Period, Land	[1]	320
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,973
Total		5,293
Accumulated depreciation	[2]	$ 2,455
Office And Office/Flex Buildings [Member] | 5 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1969
Acquired		1997
Initial Costs, Land		$ 118
Initial Costs, Building and Improvements		1,949
Costs Capitalized Subsequent to Acquisition		425
Gross Amount at Which Carried at Close of Period, Land	[1]	118
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,374
Total		2,492
Accumulated depreciation	[2]	$ 1,219
Office And Office/Flex Buildings [Member] | 6 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1968
Acquired		1997
Initial Costs, Land		$ 164
Initial Costs, Building and Improvements		1,998
Costs Capitalized Subsequent to Acquisition		166
Gross Amount at Which Carried at Close of Period, Land	[1]	164
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,164
Total		2,328
Accumulated depreciation	[2]	$ 1,012
Office And Office/Flex Buildings [Member] | 7 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1972
Acquired		1997
Initial Costs, Land		$ 286
Initial Costs, Building and Improvements		4,321
Costs Capitalized Subsequent to Acquisition		681
Gross Amount at Which Carried at Close of Period, Land	[1]	286
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	5,002
Total		5,288
Accumulated depreciation	[2]	$ 2,187
Office And Office/Flex Buildings [Member] | 8 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1971
Acquired		1997
Initial Costs, Land		$ 447
Initial Costs, Building and Improvements		5,262
Costs Capitalized Subsequent to Acquisition		1,917
Gross Amount at Which Carried at Close of Period, Land	[1]	447
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,179
Total		7,626
Accumulated depreciation	[2]	$ 3,157
Office And Office/Flex Buildings [Member] | 200 Saw Mill River Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1965
Acquired		1997
Initial Costs, Land		$ 353
Initial Costs, Building and Improvements		3,353
Costs Capitalized Subsequent to Acquisition		533
Gross Amount at Which Carried at Close of Period, Land	[1]	353
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,886
Total		4,239
Accumulated depreciation	[2]	$ 1,831
Office And Office/Flex Buildings [Member] | 4 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1997
Initial Costs, Land		$ 363
Initial Costs, Building and Improvements		7,513
Costs Capitalized Subsequent to Acquisition		2,873
Gross Amount at Which Carried at Close of Period, Land	[1]	363
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	10,386
Total		10,749
Accumulated depreciation	[2]	$ 5,320
Office And Office/Flex Buildings [Member] | 5 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1980
Acquired		2001
Initial Costs, Land		$ 2,219
Initial Costs, Building and Improvements		8,916
Costs Capitalized Subsequent to Acquisition		1,747
Gross Amount at Which Carried at Close of Period, Land	[1]	2,219
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	10,663
Total		12,882
Accumulated depreciation	[2]	$ 4,706
Office And Office/Flex Buildings [Member] | 6 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1980
Acquired		2001
Initial Costs, Land		$ 740
Initial Costs, Building and Improvements		2,971
Costs Capitalized Subsequent to Acquisition		1,498
Gross Amount at Which Carried at Close of Period, Land	[1]	740
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,469
Total		5,209
Accumulated depreciation	[2]	$ 2,380
Office And Office/Flex Buildings [Member] | 8 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1985
Acquired		1997
Initial Costs, Land		$ 212
Initial Costs, Building and Improvements		4,410
Costs Capitalized Subsequent to Acquisition		769
Gross Amount at Which Carried at Close of Period, Land	[1]	212
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	5,179
Total		5,391
Accumulated depreciation	[2]	$ 2,557
Office And Office/Flex Buildings [Member] | 10 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1985
Acquired		1997
Initial Costs, Land		$ 134
Initial Costs, Building and Improvements		2,799
Costs Capitalized Subsequent to Acquisition		732
Gross Amount at Which Carried at Close of Period, Land	[1]	134
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,531
Total		3,665
Accumulated depreciation	[2]	$ 1,903
Office And Office/Flex Buildings [Member] | 11 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1989
Acquired	[3]	1997
Initial Costs, Building and Improvements	[3]	$ 4,788
Costs Capitalized Subsequent to Acquisition	[3]	761
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1],[3]	5,549
Total	[3]	5,549
Accumulated depreciation	[2],[3]	$ 2,409
Office And Office/Flex Buildings [Member] | 12 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1999
Acquired	[3]	1999
Initial Costs, Land	[3]	$ 1,562
Initial Costs, Building and Improvements	[3]	3,254
Costs Capitalized Subsequent to Acquisition	[3]	200
Gross Amount at Which Carried at Close of Period, Land	[1],[3]	1,320
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1],[3]	3,696
Total	[3]	5,016
Accumulated depreciation	[2],[3]	$ 1,497
Office And Office/Flex Buildings [Member] | 15 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1989
Acquired	[3]	1997
Initial Costs, Building and Improvements	[3]	$ 7,449
Costs Capitalized Subsequent to Acquisition	[3]	1,060
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1],[3]	8,509
Total	[3]	8,509
Accumulated depreciation	[2],[3]	$ 3,620
Office And Office/Flex Buildings [Member] | 100 Corporate Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1997
Initial Costs, Land		$ 602
Initial Costs, Building and Improvements		9,910
Costs Capitalized Subsequent to Acquisition		1,397
Gross Amount at Which Carried at Close of Period, Land	[1]	602
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	11,307
Total		11,909
Accumulated depreciation	[2]	$ 5,342
Office And Office/Flex Buildings [Member] | 200 Corporate Boulevard South [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1997
Initial Costs, Land		$ 502
Initial Costs, Building and Improvements		7,575
Costs Capitalized Subsequent to Acquisition		1,472
Gross Amount at Which Carried at Close of Period, Land	[1]	502
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	9,047
Total		9,549
Accumulated depreciation	[2]	$ 4,473
Office And Office/Flex Buildings [Member] | 4 Executive Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1986
Acquired		1997
Initial Costs, Land		$ 584
Initial Costs, Building and Improvements		6,134
Costs Capitalized Subsequent to Acquisition		1,142
Gross Amount at Which Carried at Close of Period, Land	[1]	584
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	7,276
Total		7,860
Accumulated depreciation	[2]	$ 3,294
Office And Office/Flex Buildings [Member] | 6 Executive Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1987
Acquired		1997
Initial Costs, Land		$ 546
Initial Costs, Building and Improvements		7,246
Costs Capitalized Subsequent to Acquisition		2,206
Gross Amount at Which Carried at Close of Period, Land	[1]	546
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	9,452
Total		9,998
Accumulated depreciation	[2]	$ 4,218
Office And Office/Flex Buildings [Member] | 1 Odell Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1980
Acquired		1997
Initial Costs, Land		$ 1,206
Initial Costs, Building and Improvements		6,815
Costs Capitalized Subsequent to Acquisition		2,221
Gross Amount at Which Carried at Close of Period, Land	[1]	1,206
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	9,036
Total		10,242
Accumulated depreciation	[2]	$ 4,058
Office And Office/Flex Buildings [Member] | 5 Odell Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1983
Acquired		1997
Initial Costs, Land		$ 331
Initial Costs, Building and Improvements		2,988
Costs Capitalized Subsequent to Acquisition		535
Gross Amount at Which Carried at Close of Period, Land	[1]	331
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,523
Total		3,854
Accumulated depreciation	[2]	$ 1,760
Office And Office/Flex Buildings [Member] | 7 Odell Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1984
Acquired		1997
Initial Costs, Land		$ 419
Initial Costs, Building and Improvements		4,418
Costs Capitalized Subsequent to Acquisition		1,249
Gross Amount at Which Carried at Close of Period, Land	[1]	419
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	5,667
Total		6,086
Accumulated depreciation	[2]	$ 2,482
Office And Office/Flex Buildings [Member] | 419 West Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1986
Acquired		1997
Initial Costs, Land		$ 4,538
Initial Costs, Building and Improvements		9,246
Costs Capitalized Subsequent to Acquisition		1,298
Gross Amount at Which Carried at Close of Period, Land	[1]	4,538
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	10,544
Total		15,082
Accumulated depreciation	[2]	$ 5,417
Office And Office/Flex Buildings [Member] | 500 West Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		1997
Initial Costs, Land		$ 415
Initial Costs, Building and Improvements		1,679
Costs Capitalized Subsequent to Acquisition		654
Gross Amount at Which Carried at Close of Period, Land	[1]	415
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,333
Total		2,748
Accumulated depreciation	[2]	$ 899
Office And Office/Flex Buildings [Member] | 550 West Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1990
Acquired		1997
Initial Costs, Land		$ 1,975
Initial Costs, Building and Improvements		3,856
Costs Capitalized Subsequent to Acquisition		185
Gross Amount at Which Carried at Close of Period, Land	[1]	1,975
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	4,041
Total		6,016
Accumulated depreciation	[2]	$ 1,956
Office And Office/Flex Buildings [Member] | 600 West Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1999
Acquired		1999
Initial Costs, Land		$ 2,305
Initial Costs, Building and Improvements		2,863
Costs Capitalized Subsequent to Acquisition		754
Gross Amount at Which Carried at Close of Period, Land	[1]	2,305
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,617
Total		5,922
Accumulated depreciation	[2]	$ 1,426
Office And Office/Flex Buildings [Member] | 650 West Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1998
Acquired		1998
Initial Costs, Land		$ 1,328
Costs Capitalized Subsequent to Acquisition		3,524
Gross Amount at Which Carried at Close of Period, Land	[1]	1,328
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	3,524
Total		4,852
Accumulated depreciation	[2]	$ 1,601
Industrial/Warehouse Facilities [Member] | 1 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1957
Acquired	[3]	1997
Initial Costs, Land	[3]	$ 3
Initial Costs, Building and Improvements	[3]	268
Costs Capitalized Subsequent to Acquisition	[3]	233
Gross Amount at Which Carried at Close of Period, Land	[1],[3]	3
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1],[3]	501
Total	[3]	504
Accumulated depreciation	[2],[3]	$ 238
Industrial/Warehouse Facilities [Member] | 2 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1957
Acquired	[3]	1997
Initial Costs, Land	[3]	$ 4
Initial Costs, Building and Improvements	[3]	672
Costs Capitalized Subsequent to Acquisition	[3]	232
Gross Amount at Which Carried at Close of Period, Land	[1],[3]	4
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1],[3]	904
Total	[3]	908
Accumulated depreciation	[2],[3]	$ 378
Industrial/Warehouse Facilities [Member] | 3 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1957
Acquired	[3]	1997
Initial Costs, Land	[3]	$ 21
Initial Costs, Building and Improvements	[3]	1,948
Costs Capitalized Subsequent to Acquisition	[3]	363
Gross Amount at Which Carried at Close of Period, Land	[1],[3]	21
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1],[3]	2,311
Total	[3]	2,332
Accumulated depreciation	[2],[3]	$ 1,181
Industrial/Warehouse Facilities [Member] | 4 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1957
Acquired	[3]	1997
Initial Costs, Land	[3]	$ 84
Initial Costs, Building and Improvements	[3]	13,393
Costs Capitalized Subsequent to Acquisition	[3]	3,405
Gross Amount at Which Carried at Close of Period, Land	[1],[3]	85
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1],[3]	16,797
Total	[3]	16,882
Accumulated depreciation	[2],[3]	$ 7,261
Industrial/Warehouse Facilities [Member] | 5 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1957
Acquired	[3]	1997
Initial Costs, Land	[3]	$ 19
Initial Costs, Building and Improvements	[3]	4,804
Costs Capitalized Subsequent to Acquisition	[3]	943
Gross Amount at Which Carried at Close of Period, Land	[1],[3]	19
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1],[3]	5,747
Total	[3]	5,766
Accumulated depreciation	[2],[3]	$ 2,745
Industrial/Warehouse Facilities [Member] | 6 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	[3]	1982
Acquired	[3]	1997
Initial Costs, Land	[3]	$ 10
Initial Costs, Building and Improvements	[3]	4,419
Costs Capitalized Subsequent to Acquisition	[3]	2,381
Gross Amount at Which Carried at Close of Period, Land	[1],[3]	10
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1],[3]	6,800
Total	[3]	6,810
Accumulated depreciation	[2],[3]	$ 2,764
Retail [Member] | 230 White Plains Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1984
Acquired		1997
Initial Costs, Land		$ 124
Initial Costs, Building and Improvements		1,845
Costs Capitalized Subsequent to Acquisition		107
Gross Amount at Which Carried at Close of Period, Land	[1]	124
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	1,952
Total		2,076
Accumulated depreciation	[2]	$ 919
Retail [Member] | 2 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1986
Acquired		1997
Initial Costs, Land		$ 89
Initial Costs, Building and Improvements		2,439
Costs Capitalized Subsequent to Acquisition		107
Gross Amount at Which Carried at Close of Period, Land	[1]	89
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	2,546
Total		2,635
Accumulated depreciation	[2]	$ 1,182
Land [Member] | Capital Office Park Parcel A [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired		2009
Initial Costs, Land		$ 840
Costs Capitalized Subsequent to Acquisition		7
Gross Amount at Which Carried at Close of Period, Land	[1]	847
Total		$ 847
Multi-Family Properties [Member] | Richmond Court [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1997
Acquired		2013
Initial Costs, Land		$ 2,992
Initial Costs, Building and Improvements		13,534
Costs Capitalized Subsequent to Acquisition		1,601
Gross Amount at Which Carried at Close of Period, Land	[1]	2,992
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	15,135
Total		18,127
Accumulated depreciation	[2]	$ 689
Multi-Family Properties [Member] | Riverwatch Commons [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1995
Acquired		2013
Initial Costs, Land		$ 4,169
Initial Costs, Building and Improvements		18,974
Costs Capitalized Subsequent to Acquisition		729
Gross Amount at Which Carried at Close of Period, Land	[1]	4,169
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	19,703
Total		23,872
Accumulated depreciation	[2]	$ 965
Multi-Family Properties [Member] | Park Square [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2011
Acquired		2013
Related Encumbrances		$ 27,500
Initial Costs, Land		4,000
Initial Costs, Building and Improvements		40,670
Costs Capitalized Subsequent to Acquisition		256
Gross Amount at Which Carried at Close of Period, Land	[1]	4,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	40,926
Total		44,926
Accumulated depreciation	[3]	$ 2,148
Multi-Family Properties [Member] | Alterra At Overlook Ridge IA [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2004
Acquired		2013
Initial Costs, Land		$ 9,042
Initial Costs, Building and Improvements		50,671
Costs Capitalized Subsequent to Acquisition		879
Gross Amount at Which Carried at Close of Period, Land	[1]	9,042
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	51,550
Total		60,592
Accumulated depreciation	[2]	$ 3,859
Multi-Family Properties [Member] | Alterra at Overlook Ridge II [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2008
Acquired		2013
Initial Costs, Land		$ 12,055
Initial Costs, Building and Improvements		71,409
Costs Capitalized Subsequent to Acquisition		250
Gross Amount at Which Carried at Close of Period, Land	[1]	12,055
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	71,659
Total		83,714
Accumulated depreciation	[2]	$ 5,236
Multi-Family Properties [Member] | Apartments At Andover Place [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1988
Acquired		2014
Initial Costs, Land		$ 8,535
Initial Costs, Building and Improvements		27,609
Costs Capitalized Subsequent to Acquisition		2,263
Gross Amount at Which Carried at Close of Period, Land	[1]	8,534
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	29,873
Total		38,407
Accumulated depreciation	[2]	$ 1,623
Other Property [Member] | 500 Avenue At Port Imperial [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2013
Acquired		2013
Related Encumbrances		$ 36,600
Initial Costs, Land		13,099
Initial Costs, Building and Improvements		56,669
Costs Capitalized Subsequent to Acquisition		(21,005)
Gross Amount at Which Carried at Close of Period, Land	[1]	13,099
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	35,664
Total		48,763
Accumulated depreciation	[2]	2,174
Projects Under Development And Developable Land [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Related Encumbrances		45,899
Initial Costs, Land		204,041
Initial Costs, Building and Improvements		237,906
Gross Amount at Which Carried at Close of Period, Land	[1]	204,041
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	237,906
Total		441,947
Accumulated depreciation	[2]	323
Furniture, Fixtures And Equipment [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Costs Capitalized Subsequent to Acquisition		15,167
Gross Amount at Which Carried at Close of Period, Building and Improvements	[1]	15,167
Total		15,167
Accumulated depreciation	[2]	$ 5,418
Buildings And Improvements [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Useful Live		40 years
Land Lease [Member] | 700 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired		1997
Initial Costs, Land		$ 970
Gross Amount at Which Carried at Close of Period, Land	[1]	970
Total		$ 970
Land Lease [Member] | 1 Enterprise Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired		1997
Initial Costs, Land		$ 1,379
Costs Capitalized Subsequent to Acquisition		1
Gross Amount at Which Carried at Close of Period, Land	[1]	1,380
Total		$ 1,380
Minimum [Member] | Office [Member] | 9200 Edmonston Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1973
Minimum [Member] | Office [Member] | 6301 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1979
Minimum [Member] | Office [Member] | 6303 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1980
Minimum [Member] | Office [Member] | 6305 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1982
Minimum [Member] | Office [Member] | 6411 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1984
Maximum [Member] | Office [Member] | 9200 Edmonston Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2003
Maximum [Member] | Office [Member] | 6301 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1995
Maximum [Member] | Office [Member] | 6303 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2003
Maximum [Member] | Office [Member] | 6305 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		1995
Maximum [Member] | Office [Member] | 6411 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built		2005

[1] The aggregate cost for federal income tax purposes at December 31, 2015 was approximately $3.3 billion.

[2] Depreciation of buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.

[3] This property is located on land leased by the Company.