Schedule III - Consolidated Real Estate Investments and Accumulated Depreciation (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 301,671
Land	56,158
Building and improvements	92,635
Cost capitalized Subsequent to Acquisition	446,207
Land	56,158
Building and improvements	538,842
Total	595,000
Accumulated Depreciation	116,099
Net Carrying Amount	478,901
Real estate investments
Balance at beginning of the year	462,976	354,740
Construction costs and improvements	106,977	45,332
Acquisitions	45,300	62,936
Dispositions	(5,471)	(32)
Reclassifications	(14,782)
Balance at end of the year	595,000	462,976
Building [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Buildings	39 years
Tenant Improvements [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Tenant improvements	Term of the related lease(or estimated useful life, if shorter)
Office Real Estate [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	54,219
Land	9,431
Building and improvements	10,269
Cost capitalized Subsequent to Acquisition	203,208
Land	9,431
Building and improvements	213,477
Total	222,908
Accumulated Depreciation	52,844
Net Carrying Amount	170,064
Office Real Estate [Member] | 4525 Main Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	30,870
Land	982
Cost capitalized Subsequent to Acquisition	38,481
Land	982
Building and improvements	38,481
Total	39,463
Accumulated Depreciation	487
Net Carrying Amount	38,976
Year of Acquisition	2014
Office Real Estate [Member] | Armada Hoffler Tower
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Land	1,976
Cost capitalized Subsequent to Acquisition	55,029
Land	1,976
Building and improvements	55,029
Total	57,005
Accumulated Depreciation	23,748
Net Carrying Amount	33,257
Year of Acquisition	2002
Office Real Estate [Member] | Commonwealth of Virginia - Chesapeake [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	3,585
Land	328
Cost capitalized Subsequent to Acquisition	6,248
Land	328
Building and improvements	6,248
Total	6,576
Net Carrying Amount	6,576
Office Real Estate [Member] | Commonwealth of Virginia - Virginia Beach [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Land	208
Cost capitalized Subsequent to Acquisition	2,083
Land	208
Building and improvements	2,083
Total	2,291
Net Carrying Amount	2,291
Office Real Estate [Member] | Oceaneering [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	13,490
Land	1,829
Cost capitalized Subsequent to Acquisition	19,345
Land	1,829
Building and improvements	19,345
Total	21,174
Net Carrying Amount	21,174
Office Real Estate [Member] | One Columbus
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Land	960
Building and improvements	10,269
Cost capitalized Subsequent to Acquisition	6,795
Land	960
Building and improvements	17,064
Total	18,024
Accumulated Depreciation	8,463
Net Carrying Amount	9,561
Office Real Estate [Member] | Oyster Point [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	6,274
Land	57
Cost capitalized Subsequent to Acquisition	11,512
Land	57
Building and improvements	11,512
Total	11,569
Accumulated Depreciation	8,637
Net Carrying Amount	2,932
Year of Acquisition	1989
Office Real Estate [Member] | Richmond Tower [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Land	3,038
Cost capitalized Subsequent to Acquisition	45,473
Land	3,038
Building and improvements	45,473
Total	48,511
Accumulated Depreciation	7,245
Net Carrying Amount	41,266
Year of Acquisition	2010
Office Real Estate [Member] | Two Columbus
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Land	53
Cost capitalized Subsequent to Acquisition	18,242
Land	53
Building and improvements	18,242
Total	18,295
Accumulated Depreciation	4,264
Net Carrying Amount	14,031
Year of Acquisition	2009
Retail Real Estate [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	117,013
Land	38,225
Building and improvements	23,767
Cost capitalized Subsequent to Acquisition	131,710
Land	38,225
Building and improvements	155,477
Total	193,702
Accumulated Depreciation	45,596
Net Carrying Amount	148,106
Retail Real Estate [Member] | 249 Central Park Retail [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	15,566
Land	713
Cost capitalized Subsequent to Acquisition	13,476
Land	713
Building and improvements	13,476
Total	14,189
Accumulated Depreciation	6,395
Net Carrying Amount	7,794
Year of Acquisition	2004
Retail Real Estate [Member] | Bermuda Crossroads [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Land	5,450
Building and improvements	10,641
Cost capitalized Subsequent to Acquisition	474
Land	5,450
Building and improvements	11,115
Total	16,565
Accumulated Depreciation	826
Net Carrying Amount	15,739
Retail Real Estate [Member] | Broad Creek Shopping Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	16,047
Cost capitalized Subsequent to Acquisition	15,619
Building and improvements	15,619
Total	15,619
Accumulated Depreciation	7,355
Net Carrying Amount	8,264
Retail Real Estate [Member] | Commerce Street Retail [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	5,549
Land	118
Cost capitalized Subsequent to Acquisition	3,146
Land	118
Building and improvements	3,146
Total	3,264
Accumulated Depreciation	845
Net Carrying Amount	2,419
Year of Acquisition	2008
Retail Real Estate [Member] | Courthouse 7-Eleven
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Land	1,007
Cost capitalized Subsequent to Acquisition	1,043
Land	1,007
Building and improvements	1,043
Total	2,050
Accumulated Depreciation	83
Net Carrying Amount	1,967
Year of Acquisition	2011
Retail Real Estate [Member] | Dick's at Town Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	8,216
Land	67
Cost capitalized Subsequent to Acquisition	10,453
Land	67
Building and improvements	10,453
Total	10,520
Accumulated Depreciation	2,680
Net Carrying Amount	7,840
Year of Acquisition	2002
Retail Real Estate [Member] | Dimmock Square [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Land	5,100
Building and improvements	13,126
Cost capitalized Subsequent to Acquisition	3
Land	5,100
Building and improvements	13,129
Total	18,229
Accumulated Depreciation	151
Net Carrying Amount	18,078
Retail Real Estate [Member] | Fountain Plaza Retail [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	7,783
Land	425
Cost capitalized Subsequent to Acquisition	7,018
Land	425
Building and improvements	7,018
Total	7,443
Accumulated Depreciation	2,525
Net Carrying Amount	4,918
Year of Acquisition	2004
Retail Real Estate [Member] | Gainsborough Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Land	2,229
Cost capitalized Subsequent to Acquisition	6,813
Land	2,229
Building and improvements	6,813
Total	9,042
Accumulated Depreciation	2,644
Net Carrying Amount	6,398
Year of Acquisition	1999
Retail Real Estate [Member] | Greentree Shopping Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Land	1,523
Cost capitalized Subsequent to Acquisition	3,520
Land	1,523
Building and improvements	3,520
Total	5,043
Accumulated Depreciation	37
Net Carrying Amount	5,006
Year of Acquisition	2014
Retail Real Estate [Member] | Hanbury Village [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	25,308
Land	3,792
Cost capitalized Subsequent to Acquisition	18,021
Land	3,792
Building and improvements	18,021
Total	21,813
Accumulated Depreciation	4,589
Net Carrying Amount	17,224
Year of Acquisition	2009
Retail Real Estate [Member] | Harrisonburg Regal [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	3,659
Land	1,554
Cost capitalized Subsequent to Acquisition	4,148
Land	1,554
Building and improvements	4,148
Total	5,702
Accumulated Depreciation	1,664
Net Carrying Amount	4,038
Year of Acquisition	1999
Retail Real Estate [Member] | Lightfoot Marketplace [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	3,484
Land	7,628
Cost capitalized Subsequent to Acquisition	2,891
Land	7,628
Building and improvements	2,891
Total	10,519
Net Carrying Amount	10,519
Retail Real Estate [Member] | North Point Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	13,587
Land	1,936
Cost capitalized Subsequent to Acquisition	24,797
Land	1,936
Building and improvements	24,797
Total	26,733
Accumulated Depreciation	10,124
Net Carrying Amount	16,609
Year of Acquisition	1998
Retail Real Estate [Member] | Parkway Marketplace
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Land	1,150
Cost capitalized Subsequent to Acquisition	3,500
Land	1,150
Building and improvements	3,500
Total	4,650
Accumulated Depreciation	1,501
Net Carrying Amount	3,149
Year of Acquisition	1998
Retail Real Estate [Member] | Sandbridge Commons [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	5,892
Land	5,267
Cost capitalized Subsequent to Acquisition	4,095
Land	5,267
Building and improvements	4,095
Total	9,362
Net Carrying Amount	9,362
Retail Real Estate [Member] | South Retail [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	6,867
Land	190
Cost capitalized Subsequent to Acquisition	7,090
Land	190
Building and improvements	7,090
Total	7,280
Accumulated Depreciation	3,214
Net Carrying Amount	4,066
Year of Acquisition	2002
Retail Real Estate [Member] | Studio 56 Retail [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	2,618
Land	76
Cost capitalized Subsequent to Acquisition	2,297
Land	76
Building and improvements	2,297
Total	2,373
Accumulated Depreciation	539
Net Carrying Amount	1,834
Year of Acquisition	2007
Retail Real Estate [Member] | Tyre Neck Harris Teeter [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	2,437
Cost capitalized Subsequent to Acquisition	3,306
Building and improvements	3,306
Total	3,306
Accumulated Depreciation	424
Net Carrying Amount	2,882
Year of Acquisition	2011
Multifamily Residential Real Estate [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	130,439
Land	8,502
Building and improvements	58,599
Cost capitalized Subsequent to Acquisition	111,289
Land	8,502
Building and improvements	169,888
Total	178,390
Accumulated Depreciation	17,659
Net Carrying Amount	160,731
Multifamily Residential Real Estate [Member] | Encore Apartments [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	22,215
Land	1,293
Cost capitalized Subsequent to Acquisition	28,882
Land	1,293
Building and improvements	28,882
Total	30,175
Accumulated Depreciation	89
Net Carrying Amount	30,086
Year of Acquisition	2014
Multifamily Residential Real Estate [Member] | Liberty Apartments [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	20,603
Land	3,580
Building and improvements	23,494
Cost capitalized Subsequent to Acquisition	1,049
Land	3,580
Building and improvements	24,543
Total	28,123
Accumulated Depreciation	781
Net Carrying Amount	27,342
Multifamily Residential Real Estate [Member] | Smith's Landing [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	24,470
Building and improvements	35,105
Cost capitalized Subsequent to Acquisition	659
Building and improvements	35,764
Total	35,764
Accumulated Depreciation	1,859
Net Carrying Amount	33,905
Multifamily Residential Real Estate [Member] | The Cosmopolitan [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	47,132
Land	985
Cost capitalized Subsequent to Acquisition	56,419
Land	985
Building and improvements	56,419
Total	57,404
Accumulated Depreciation	14,866
Net Carrying Amount	42,538
Year of Acquisition	2006
Multifamily Residential Real Estate [Member] | Whetstone Apartments [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	16,019
Land	2,644
Cost capitalized Subsequent to Acquisition	24,280
Land	2,644
Building and improvements	24,280
Total	26,924
Accumulated Depreciation	64
Net Carrying Amount	$ 26,860
Year of Acquisition	2014
Minimum [Member] | Capital Improvements [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Buildings	15 years
Minimum [Member] | Equipment [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Buildings	5 years
Minimum [Member] | Office Real Estate [Member] | One Columbus
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	1984
Minimum [Member] | Retail Real Estate [Member] | Bermuda Crossroads [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	2001
Minimum [Member] | Retail Real Estate [Member] | Broad Creek Shopping Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	1997
Minimum [Member] | Retail Real Estate [Member] | Dimmock Square [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	1998
Minimum [Member] | Multifamily Residential Real Estate [Member] | Liberty Apartments [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	2013
Minimum [Member] | Multifamily Residential Real Estate [Member] | Smith's Landing [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	2009
Maximum [Member] | Capital Improvements [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Buildings	20 years
Maximum [Member] | Equipment [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Buildings	15 years
Maximum [Member] | Office Real Estate [Member] | One Columbus
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	2000
Maximum [Member] | Retail Real Estate [Member] | Bermuda Crossroads [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	2013
Maximum [Member] | Retail Real Estate [Member] | Broad Creek Shopping Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	2001
Maximum [Member] | Retail Real Estate [Member] | Dimmock Square [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	2014
Maximum [Member] | Multifamily Residential Real Estate [Member] | Liberty Apartments [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	2014
Maximum [Member] | Multifamily Residential Real Estate [Member] | Smith's Landing [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year of Acquisition	2013