Real Estate and Accumulated Depreciation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Real Estate Properties [Line Items]
Initial Basis	$ 1,088,613
Cost capitalized subsequent to acquisition	1,319,523
Land and Land Improvements	511,529
Buildings and Improvements, Gross	1,576,924
Construction in progress	319,683	$ 205,911
Real Estate Investment Property, at Cost, Total	2,408,136	2,284,126	$ 2,124,796	$ 2,081,597
Accumulated Depreciation	688,475	650,113	$ 607,706	$ 563,474
Book Value	1,719,661	1,634,013
Fixed rate mortgages	961,577	$ 941,456
Total, related debt	974,682
Shopping Centers
Real Estate Properties [Line Items]
Initial Basis	835,537
Cost capitalized subsequent to acquisition	482,444
Land and Land Improvements	420,132
Buildings and Improvements, Gross	889,818
Construction in progress	8,031
Real Estate Investment Property, at Cost, Total	1,317,981
Accumulated Depreciation	456,197
Book Value	861,784
Fixed rate mortgages	597,990
Shopping Centers | Ashbrook Marketplace, Ashburn, VA
Real Estate Properties [Line Items]
Initial Basis	8,938
Cost capitalized subsequent to acquisition	25,314
Land and Land Improvements	13,258
Buildings and Improvements, Gross	20,994
Construction in progress	0
Real Estate Investment Property, at Cost, Total	34,252
Accumulated Depreciation	1,965
Book Value	32,287
Fixed rate mortgages	$ 20,807
Buildings and improvements depreciable lives in years	50 years
Shopping Centers | Ashburn Village, Ashburn, VA
Real Estate Properties [Line Items]
Initial Basis	$ 11,431
Cost capitalized subsequent to acquisition	20,755
Land and Land Improvements	6,764
Buildings and Improvements, Gross	25,422
Construction in progress	0
Real Estate Investment Property, at Cost, Total	32,186
Accumulated Depreciation	16,475
Book Value	15,711
Fixed rate mortgages	$ 23,039
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Ashburn Village, Ashburn, VA | Minimum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	5 years
Shopping Centers | Ashburn Village, Ashburn, VA | Maximum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	10 years
Shopping Centers | Ashland Square Phase I, Dumfries, VA
Real Estate Properties [Line Items]
Initial Basis	$ 1,178
Cost capitalized subsequent to acquisition	5,298
Land and Land Improvements	1,178
Buildings and Improvements, Gross	5,298
Construction in progress	0
Real Estate Investment Property, at Cost, Total	6,476
Accumulated Depreciation	2,885
Book Value	3,591
Fixed rate mortgages	$ 0
Shopping Centers | Ashland Square Phase I, Dumfries, VA | Minimum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	20 years
Shopping Centers | Ashland Square Phase I, Dumfries, VA | Maximum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	50 years
Shopping Centers | Beacon Center, Alexandria, VA
Real Estate Properties [Line Items]
Initial Basis	$ 24,161
Cost capitalized subsequent to acquisition	18,514
Land and Land Improvements	22,691
Buildings and Improvements, Gross	19,984
Construction in progress	0
Real Estate Investment Property, at Cost, Total	42,675
Accumulated Depreciation	16,754
Book Value	25,921
Fixed rate mortgages	$ 54,816
Shopping Centers | Beacon Center, Alexandria, VA | Minimum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Beacon Center, Alexandria, VA | Maximum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	50 years
Shopping Centers | BJ’s Wholesale Club, Alexandria, VA
Real Estate Properties [Line Items]
Initial Basis	$ 22,623
Cost capitalized subsequent to acquisition	0
Land and Land Improvements	22,623
Buildings and Improvements, Gross	0
Construction in progress	0
Real Estate Investment Property, at Cost, Total	22,623
Accumulated Depreciation	0
Book Value	22,623
Fixed rate mortgages	$ 9,345
Buildings and improvements depreciable lives in years	0 years
Shopping Centers | Boca Valley Plaza, Boca Raton, FL
Real Estate Properties [Line Items]
Initial Basis	$ 16,720
Cost capitalized subsequent to acquisition	3,236
Land and Land Improvements	5,735
Buildings and Improvements, Gross	14,221
Construction in progress	0
Real Estate Investment Property, at Cost, Total	19,956
Accumulated Depreciation	6,633
Book Value	13,323
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Boulevard, Fairfax, VA
Real Estate Properties [Line Items]
Initial Basis	$ 4,883
Cost capitalized subsequent to acquisition	4,753
Land and Land Improvements	3,687
Buildings and Improvements, Gross	5,949
Construction in progress	0
Real Estate Investment Property, at Cost, Total	9,636
Accumulated Depreciation	3,907
Book Value	5,729
Fixed rate mortgages	$ 9,846
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Briggs Chaney MarketPlace, Silver Spring, MD
Real Estate Properties [Line Items]
Initial Basis	$ 27,037
Cost capitalized subsequent to acquisition	5,355
Land and Land Improvements	9,789
Buildings and Improvements, Gross	22,603
Construction in progress	0
Real Estate Investment Property, at Cost, Total	32,392
Accumulated Depreciation	11,358
Book Value	21,034
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Broadlands Village, Ashburn, VA
Real Estate Properties [Line Items]
Initial Basis	$ 5,316
Cost capitalized subsequent to acquisition	35,915
Land and Land Improvements	5,300
Buildings and Improvements, Gross	35,925
Construction in progress	6
Real Estate Investment Property, at Cost, Total	41,231
Accumulated Depreciation	15,774
Book Value	25,457
Fixed rate mortgages	$ 28,858
Shopping Centers | Broadlands Village, Ashburn, VA | Minimum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Broadlands Village, Ashburn, VA | Maximum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	50 years
Shopping Centers | Burtonsville Town Square, Burtonsville, MD
Real Estate Properties [Line Items]
Initial Basis	$ 74,212
Cost capitalized subsequent to acquisition	6,344
Land and Land Improvements	28,402
Buildings and Improvements, Gross	52,138
Construction in progress	16
Real Estate Investment Property, at Cost, Total	80,556
Accumulated Depreciation	8,338
Book Value	72,218
Fixed rate mortgages	$ 33,439
Shopping Centers | Burtonsville Town Square, Burtonsville, MD | Minimum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	20 years
Shopping Centers | Burtonsville Town Square, Burtonsville, MD | Maximum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	45 years
Shopping Centers | Countryside Marketplace, Sterling, VA
Real Estate Properties [Line Items]
Initial Basis	$ 28,912
Cost capitalized subsequent to acquisition	4,314
Land and Land Improvements	7,666
Buildings and Improvements, Gross	25,560
Construction in progress	0
Real Estate Investment Property, at Cost, Total	33,226
Accumulated Depreciation	12,981
Book Value	20,245
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Cranberry Square, Westminster, MD
Real Estate Properties [Line Items]
Initial Basis	$ 31,578
Cost capitalized subsequent to acquisition	1,922
Land and Land Improvements	6,700
Buildings and Improvements, Gross	26,800
Construction in progress	0
Real Estate Investment Property, at Cost, Total	33,500
Accumulated Depreciation	7,556
Book Value	25,944
Fixed rate mortgages	$ 13,946
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Cruse MarketPlace, Cumming, GA
Real Estate Properties [Line Items]
Initial Basis	$ 12,226
Cost capitalized subsequent to acquisition	790
Land and Land Improvements	3,901
Buildings and Improvements, Gross	9,115
Construction in progress	0
Real Estate Investment Property, at Cost, Total	13,016
Accumulated Depreciation	4,444
Book Value	8,572
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Flagship Center, Rockville, MD
Real Estate Properties [Line Items]
Initial Basis	$ 160
Cost capitalized subsequent to acquisition	409
Land and Land Improvements	169
Buildings and Improvements, Gross	400
Construction in progress	0
Real Estate Investment Property, at Cost, Total	569
Accumulated Depreciation	65
Book Value	504
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	0 years
Shopping Centers | French Market, Oklahoma City, OK
Real Estate Properties [Line Items]
Initial Basis	$ 5,781
Cost capitalized subsequent to acquisition	16,907
Land and Land Improvements	1,118
Buildings and Improvements, Gross	21,570
Construction in progress	0
Real Estate Investment Property, at Cost, Total	22,688
Accumulated Depreciation	14,378
Book Value	8,310
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	50 years
Shopping Centers | Germantown, Germantown, MD
Real Estate Properties [Line Items]
Initial Basis	$ 2,034
Cost capitalized subsequent to acquisition	566
Land and Land Improvements	2,034
Buildings and Improvements, Gross	566
Construction in progress	0
Real Estate Investment Property, at Cost, Total	2,600
Accumulated Depreciation	479
Book Value	2,121
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | The Glen, Woodbridge, VA
Real Estate Properties [Line Items]
Initial Basis	$ 12,918
Cost capitalized subsequent to acquisition	8,627
Land and Land Improvements	5,300
Buildings and Improvements, Gross	16,245
Construction in progress	0
Real Estate Investment Property, at Cost, Total	21,545
Accumulated Depreciation	11,561
Book Value	9,984
Fixed rate mortgages	$ 20,827
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Great Falls Center, Great Falls, VA
Real Estate Properties [Line Items]
Initial Basis	$ 41,750
Cost capitalized subsequent to acquisition	3,368
Land and Land Improvements	14,766
Buildings and Improvements, Gross	30,352
Construction in progress	0
Real Estate Investment Property, at Cost, Total	45,118
Accumulated Depreciation	12,114
Book Value	33,004
Fixed rate mortgages	$ 31,313
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Hampshire Langley, Takoma, MD
Real Estate Properties [Line Items]
Initial Basis	$ 3,159
Cost capitalized subsequent to acquisition	3,475
Land and Land Improvements	1,892
Buildings and Improvements, Gross	4,732
Construction in progress	10
Real Estate Investment Property, at Cost, Total	6,634
Accumulated Depreciation	4,203
Book Value	2,431
Fixed rate mortgages	$ 12,231
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Hunt Club Corners, Apopka, FL
Real Estate Properties [Line Items]
Initial Basis	$ 12,584
Cost capitalized subsequent to acquisition	4,653
Land and Land Improvements	4,822
Buildings and Improvements, Gross	12,415
Construction in progress	0
Real Estate Investment Property, at Cost, Total	17,237
Accumulated Depreciation	6,208
Book Value	11,029
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Jamestown Place, Altamonte Springs, FL
Real Estate Properties [Line Items]
Initial Basis	$ 14,055
Cost capitalized subsequent to acquisition	2,459
Land and Land Improvements	4,455
Buildings and Improvements, Gross	12,059
Construction in progress	0
Real Estate Investment Property, at Cost, Total	16,514
Accumulated Depreciation	5,543
Book Value	10,971
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Kentlands Square I, Gaithersburg, MD
Real Estate Properties [Line Items]
Initial Basis	$ 14,379
Cost capitalized subsequent to acquisition	3,365
Land and Land Improvements	5,005
Buildings and Improvements, Gross	11,984
Construction in progress	755
Real Estate Investment Property, at Cost, Total	17,744
Accumulated Depreciation	5,165
Book Value	12,579
Fixed rate mortgages	$ 20,836
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Kentlands Square II, Gaithersburg, MD
Real Estate Properties [Line Items]
Initial Basis	$ 76,723
Cost capitalized subsequent to acquisition	3,323
Land and Land Improvements	23,133
Buildings and Improvements, Gross	56,631
Construction in progress	282
Real Estate Investment Property, at Cost, Total	80,046
Accumulated Depreciation	18,095
Book Value	61,951
Fixed rate mortgages	$ 29,658
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Kentlands Place, Gaithersburg, MD
Real Estate Properties [Line Items]
Initial Basis	$ 1,425
Cost capitalized subsequent to acquisition	7,639
Land and Land Improvements	1,425
Buildings and Improvements, Gross	7,639
Construction in progress	0
Real Estate Investment Property, at Cost, Total	9,064
Accumulated Depreciation	4,806
Book Value	4,258
Fixed rate mortgages	$ 7,321
Buildings and improvements depreciable lives in years	50 years
Shopping Centers | Lansdowne Town Center, Leesburg, VA
Real Estate Properties [Line Items]
Initial Basis	$ 6,545
Cost capitalized subsequent to acquisition	43,497
Land and Land Improvements	6,546
Buildings and Improvements, Gross	43,427
Construction in progress	69
Real Estate Investment Property, at Cost, Total	50,042
Accumulated Depreciation	20,112
Book Value	29,930
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	50 years
Shopping Centers | Leesburg Pike Plaza, Baileys Crossroads, VA
Real Estate Properties [Line Items]
Initial Basis	$ 2,418
Cost capitalized subsequent to acquisition	6,402
Land and Land Improvements	1,132
Buildings and Improvements, Gross	7,688
Construction in progress	0
Real Estate Investment Property, at Cost, Total	8,820
Accumulated Depreciation	6,487
Book Value	2,333
Fixed rate mortgages	$ 12,543
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Lumberton Plaza, Lumberton, NJ
Real Estate Properties [Line Items]
Initial Basis	$ 4,400
Cost capitalized subsequent to acquisition	11,648
Land and Land Improvements	950
Buildings and Improvements, Gross	15,074
Construction in progress	24
Real Estate Investment Property, at Cost, Total	16,048
Accumulated Depreciation	14,060
Book Value	1,988
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Metro Pike Center, Rockville, MD
Real Estate Properties [Line Items]
Initial Basis	$ 33,123
Cost capitalized subsequent to acquisition	5,399
Land and Land Improvements	26,064
Buildings and Improvements, Gross	8,476
Construction in progress	3,982
Real Estate Investment Property, at Cost, Total	38,522
Accumulated Depreciation	2,607
Book Value	35,915
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Shops at Monocacy, Frederick, MD
Real Estate Properties [Line Items]
Initial Basis	$ 9,541
Cost capitalized subsequent to acquisition	15,884
Land and Land Improvements	9,260
Buildings and Improvements, Gross	16,165
Construction in progress	0
Real Estate Investment Property, at Cost, Total	25,425
Accumulated Depreciation	7,344
Book Value	18,081
Fixed rate mortgages	$ 26,422
Buildings and improvements depreciable lives in years	50 years
Shopping Centers | Northrock, Warrenton, VA
Real Estate Properties [Line Items]
Initial Basis	$ 12,686
Cost capitalized subsequent to acquisition	15,429
Land and Land Improvements	12,686
Buildings and Improvements, Gross	15,423
Construction in progress	6
Real Estate Investment Property, at Cost, Total	28,115
Accumulated Depreciation	6,310
Book Value	21,805
Fixed rate mortgages	$ 12,652
Buildings and improvements depreciable lives in years	50 years
Shopping Centers | Olde Forte Village, Ft. Washington, MD
Real Estate Properties [Line Items]
Initial Basis	$ 15,933
Cost capitalized subsequent to acquisition	6,922
Land and Land Improvements	5,409
Buildings and Improvements, Gross	17,446
Construction in progress	0
Real Estate Investment Property, at Cost, Total	22,855
Accumulated Depreciation	9,528
Book Value	13,327
Fixed rate mortgages	$ 20,136
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Olney, Olney, MD
Real Estate Properties [Line Items]
Initial Basis	$ 4,963
Cost capitalized subsequent to acquisition	2,998
Land and Land Improvements	3,079
Buildings and Improvements, Gross	4,882
Construction in progress	0
Real Estate Investment Property, at Cost, Total	7,961
Accumulated Depreciation	3,633
Book Value	4,328
Fixed rate mortgages	$ 12,476
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Orchard Park, Dunwoody, GA
Real Estate Properties [Line Items]
Initial Basis	$ 19,377
Cost capitalized subsequent to acquisition	1,616
Land and Land Improvements	7,751
Buildings and Improvements, Gross	13,242
Construction in progress	0
Real Estate Investment Property, at Cost, Total	20,993
Accumulated Depreciation	5,286
Book Value	15,707
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Palm Springs Center, Altamonte Springs, FL
Real Estate Properties [Line Items]
Initial Basis	$ 18,365
Cost capitalized subsequent to acquisition	2,324
Land and Land Improvements	5,739
Buildings and Improvements, Gross	14,948
Construction in progress	2
Real Estate Investment Property, at Cost, Total	20,689
Accumulated Depreciation	6,957
Book Value	13,732
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Ravenwood, Baltimore, MD
Real Estate Properties [Line Items]
Initial Basis	$ 1,245
Cost capitalized subsequent to acquisition	4,446
Land and Land Improvements	703
Buildings and Improvements, Gross	4,988
Construction in progress	0
Real Estate Investment Property, at Cost, Total	5,691
Accumulated Depreciation	3,641
Book Value	2,050
Fixed rate mortgages	$ 11,975
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | 11503 Rockville Pike/5541 Nicholson Lane, Rockville, MD
Real Estate Properties [Line Items]
Initial Basis	$ 26,561
Cost capitalized subsequent to acquisition	24
Land and Land Improvements	22,113
Buildings and Improvements, Gross	4,472
Construction in progress	0
Real Estate Investment Property, at Cost, Total	26,585
Accumulated Depreciation	1,374
Book Value	25,211
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | 1500/1580/1582 Rockville Pike, Rockville, MD
Real Estate Properties [Line Items]
Initial Basis	$ 45,351
Cost capitalized subsequent to acquisition	2,046
Land and Land Improvements	38,065
Buildings and Improvements, Gross	7,050
Construction in progress	2,282
Real Estate Investment Property, at Cost, Total	47,397
Accumulated Depreciation	6,712
Book Value	40,685
Fixed rate mortgages	0
Shopping Centers | Seabreeze Plaza, Palm Harbor, FL
Real Estate Properties [Line Items]
Initial Basis	24,526
Cost capitalized subsequent to acquisition	2,625
Land and Land Improvements	8,665
Buildings and Improvements, Gross	18,486
Construction in progress	0
Real Estate Investment Property, at Cost, Total	27,151
Accumulated Depreciation	8,435
Book Value	18,716
Fixed rate mortgages	$ 13,302
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Market Place at Sea Colony, Bethany Beach, DE
Real Estate Properties [Line Items]
Initial Basis	$ 2,920
Cost capitalized subsequent to acquisition	339
Land and Land Improvements	1,147
Buildings and Improvements, Gross	2,112
Construction in progress	0
Real Estate Investment Property, at Cost, Total	3,259
Accumulated Depreciation	792
Book Value	2,467
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Seven Corners, Falls Church, VA
Real Estate Properties [Line Items]
Initial Basis	$ 4,848
Cost capitalized subsequent to acquisition	46,510
Land and Land Improvements	4,929
Buildings and Improvements, Gross	46,429
Construction in progress	0
Real Estate Investment Property, at Cost, Total	51,358
Accumulated Depreciation	34,249
Book Value	17,109
Fixed rate mortgages	$ 87,706
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Severna Park Marketplace, Severna Park, MD
Real Estate Properties [Line Items]
Initial Basis	$ 63,254
Cost capitalized subsequent to acquisition	1,094
Land and Land Improvements	12,700
Buildings and Improvements, Gross	51,549
Construction in progress	99
Real Estate Investment Property, at Cost, Total	64,348
Accumulated Depreciation	14,526
Book Value	49,822
Fixed rate mortgages	$ 25,857
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Shops at Fairfax, Fairfax, VA
Real Estate Properties [Line Items]
Initial Basis	$ 2,708
Cost capitalized subsequent to acquisition	11,090
Land and Land Improvements	992
Buildings and Improvements, Gross	12,806
Construction in progress	0
Real Estate Investment Property, at Cost, Total	13,798
Accumulated Depreciation	9,481
Book Value	4,317
Fixed rate mortgages	$ 13,597
Buildings and improvements depreciable lives in years	50 years
Shopping Centers | Smallwood Village Center, Waldorf, MD
Real Estate Properties [Line Items]
Initial Basis	$ 17,819
Cost capitalized subsequent to acquisition	8,461
Land and Land Improvements	6,402
Buildings and Improvements, Gross	19,878
Construction in progress	0
Real Estate Investment Property, at Cost, Total	26,280
Accumulated Depreciation	11,167
Book Value	15,113
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Southdale, Glen Burnie, MD
Real Estate Properties [Line Items]
Initial Basis	$ 18,895
Cost capitalized subsequent to acquisition	25,810
Land and Land Improvements	15,255
Buildings and Improvements, Gross	29,205
Construction in progress	245
Real Estate Investment Property, at Cost, Total	44,705
Accumulated Depreciation	24,221
Book Value	20,484
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Southside Plaza, Richmond, VA
Real Estate Properties [Line Items]
Initial Basis	$ 6,728
Cost capitalized subsequent to acquisition	11,891
Land and Land Improvements	1,878
Buildings and Improvements, Gross	16,741
Construction in progress	0
Real Estate Investment Property, at Cost, Total	18,619
Accumulated Depreciation	13,781
Book Value	4,838
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | South Dekalb Plaza, Atlanta, GA
Real Estate Properties [Line Items]
Initial Basis	$ 2,474
Cost capitalized subsequent to acquisition	4,985
Land and Land Improvements	615
Buildings and Improvements, Gross	6,814
Construction in progress	30
Real Estate Investment Property, at Cost, Total	7,459
Accumulated Depreciation	5,438
Book Value	2,021
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Thruway, Winston-Salem, NC
Real Estate Properties [Line Items]
Initial Basis	$ 7,848
Cost capitalized subsequent to acquisition	28,207
Land and Land Improvements	7,692
Buildings and Improvements, Gross	28,345
Construction in progress	18
Real Estate Investment Property, at Cost, Total	36,055
Accumulated Depreciation	20,927
Book Value	15,128
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Village Center, Centreville, VA
Real Estate Properties [Line Items]
Initial Basis	$ 16,502
Cost capitalized subsequent to acquisition	3,356
Land and Land Improvements	7,851
Buildings and Improvements, Gross	12,007
Construction in progress	0
Real Estate Investment Property, at Cost, Total	19,858
Accumulated Depreciation	8,524
Book Value	11,334
Fixed rate mortgages	$ 25,057
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Westview Village, Frederick, MD
Real Estate Properties [Line Items]
Initial Basis	$ 6,047
Cost capitalized subsequent to acquisition	25,658
Land and Land Improvements	6,047
Buildings and Improvements, Gross	25,658
Construction in progress	0
Real Estate Investment Property, at Cost, Total	31,705
Accumulated Depreciation	12,147
Book Value	19,558
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	50 years
Shopping Centers | White Oak, Silver Spring, MD
Real Estate Properties [Line Items]
Initial Basis	$ 6,277
Cost capitalized subsequent to acquisition	6,299
Land and Land Improvements	4,649
Buildings and Improvements, Gross	7,723
Construction in progress	204
Real Estate Investment Property, at Cost, Total	12,576
Accumulated Depreciation	6,615
Book Value	5,961
Fixed rate mortgages	$ 19,985
Buildings and improvements depreciable lives in years	40 years
Shopping Centers | Other Buildings / Improvements
Real Estate Properties [Line Items]
Cost capitalized subsequent to acquisition	$ 183
Buildings and Improvements, Gross	182
Construction in progress	1
Real Estate Investment Property, at Cost, Total	183
Accumulated Depreciation	156
Book Value	27
Fixed rate mortgages	0
Mixed-Use Properties
Real Estate Properties [Line Items]
Initial Basis	96,034
Cost capitalized subsequent to acquisition	673,186
Land and Land Improvements	82,114
Buildings and Improvements, Gross	687,106
Construction in progress	0
Real Estate Investment Property, at Cost, Total	769,220
Accumulated Depreciation	232,278
Book Value	536,942
Fixed rate mortgages	376,692
Mixed-Use Properties | Avenel Business Park, Gaithersburg, MD
Real Estate Properties [Line Items]
Initial Basis	21,459
Cost capitalized subsequent to acquisition	37,788
Land and Land Improvements	3,756
Buildings and Improvements, Gross	55,491
Construction in progress	0
Real Estate Investment Property, at Cost, Total	59,247
Accumulated Depreciation	42,385
Book Value	16,862
Fixed rate mortgages	$ 22,906
Mixed-Use Properties | Avenel Business Park, Gaithersburg, MD | Minimum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	35 years
Mixed-Use Properties | Avenel Business Park, Gaithersburg, MD | Maximum
Real Estate Properties [Line Items]
Buildings and improvements depreciable lives in years	40 years
Mixed-Use Properties | Clarendon Center, Arlington, VA (1)
Real Estate Properties [Line Items]
Initial Basis	$ 12,753
Cost capitalized subsequent to acquisition	187,682
Land and Land Improvements	16,287
Buildings and Improvements, Gross	184,148
Construction in progress	0
Real Estate Investment Property, at Cost, Total	200,435
Accumulated Depreciation	60,798
Book Value	139,637
Fixed rate mortgages	$ 86,264
Buildings and improvements depreciable lives in years	50 years
Mixed-Use Properties | Park Van Ness, Washington, DC
Real Estate Properties [Line Items]
Initial Basis	$ 2,242
Cost capitalized subsequent to acquisition	91,855
Land and Land Improvements	2,242
Buildings and Improvements, Gross	91,855
Construction in progress	0
Real Estate Investment Property, at Cost, Total	94,097
Accumulated Depreciation	18,384
Book Value	75,713
Fixed rate mortgages	$ 62,813
Buildings and improvements depreciable lives in years	50 years
Mixed-Use Properties | 601 Pennsylvania Ave., Washington, DC
Real Estate Properties [Line Items]
Initial Basis	$ 5,479
Cost capitalized subsequent to acquisition	69,446
Land and Land Improvements	5,667
Buildings and Improvements, Gross	69,258
Construction in progress	0
Real Estate Investment Property, at Cost, Total	74,925
Accumulated Depreciation	59,832
Book Value	15,093
Fixed rate mortgages	$ 0
Buildings and improvements depreciable lives in years	35 years
Mixed-Use Properties | The Waycroft, Arlington, VA
Real Estate Properties [Line Items]
Initial Basis	$ 52,067
Cost capitalized subsequent to acquisition	228,070
Land and Land Improvements	53,618
Buildings and Improvements, Gross	226,519
Construction in progress	0
Real Estate Investment Property, at Cost, Total	280,137
Accumulated Depreciation	18,241
Book Value	261,896
Fixed rate mortgages	$ 152,679
Buildings and improvements depreciable lives in years	50 years
Mixed-Use Properties | Washington Square, Alexandria, VA
Real Estate Properties [Line Items]
Initial Basis	$ 2,034
Cost capitalized subsequent to acquisition	58,345
Land and Land Improvements	544
Buildings and Improvements, Gross	59,835
Construction in progress	0
Real Estate Investment Property, at Cost, Total	60,379
Accumulated Depreciation	32,638
Book Value	27,741
Fixed rate mortgages	$ 52,030
Buildings and improvements depreciable lives in years	50 years
Development Land
Real Estate Properties [Line Items]
Initial Basis	$ 157,042
Cost capitalized subsequent to acquisition	163,893
Land and Land Improvements	9,283
Buildings and Improvements, Gross	0
Construction in progress	311,652
Real Estate Investment Property, at Cost, Total	320,935
Accumulated Depreciation	0
Book Value	320,935
Development land, related debt	0
Development Land | Ashland Square Phase II, Manassas, VA
Real Estate Properties [Line Items]
Initial Basis	5,292
Cost capitalized subsequent to acquisition	5,033
Land and Land Improvements	7,049
Buildings and Improvements, Gross	0
Construction in progress	3,276
Real Estate Investment Property, at Cost, Total	10,325
Accumulated Depreciation	0
Book Value	10,325
Development land, related debt	$ 0
Buildings and improvements depreciable lives in years
Development Land | New Market, New Market, MD
Real Estate Properties [Line Items]
Initial Basis	$ 2,088
Cost capitalized subsequent to acquisition	146
Land and Land Improvements	2,234
Buildings and Improvements, Gross	0
Construction in progress	0
Real Estate Investment Property, at Cost, Total	2,234
Accumulated Depreciation	0
Book Value	2,234
Development land, related debt	$ 0
Buildings and improvements depreciable lives in years
Development Land | Hampden House, Bethesda, MD
Real Estate Properties [Line Items]
Initial Basis	$ 39,641
Cost capitalized subsequent to acquisition	41,063
Land and Land Improvements	0
Buildings and Improvements, Gross	0
Construction in progress	80,704
Real Estate Investment Property, at Cost, Total	80,704
Accumulated Depreciation	0
Book Value	80,704
Development land, related debt	$ 0
Buildings and improvements depreciable lives in years
Development Land | Twinbrook, Rockville, MD
Real Estate Properties [Line Items]
Initial Basis	$ 110,021
Cost capitalized subsequent to acquisition	117,651
Land and Land Improvements	0
Buildings and Improvements, Gross	0
Construction in progress	227,672
Real Estate Investment Property, at Cost, Total	227,672
Accumulated Depreciation	0
Book Value	227,672
Development land, related debt	$ 0
Buildings and improvements depreciable lives in years