Indebtedness - Schedule of Debt (Details) - USD ($) $ in Thousands				2 Months Ended	12 Months Ended
	Jan. 22, 2018	Jul. 30, 2015	Jul. 10, 2015	Feb. 23, 2018	Dec. 31, 2017	Nov. 01, 2017	Sep. 01, 2017	Aug. 09, 2017	Dec. 31, 2016	Jul. 01, 2015	May 27, 2015
Debt Instrument [Line Items]
Total principal balance					$ 523,412				$ 527,082
Unamortized fair value adjustments					(1,211)				(1,250)
Unamortized debt issuance costs					(4,929)				(3,652)
Indebtedness, net					517,272				522,180
Revolving Credit Facility
Debt Instrument [Line Items]
Total principal balance					66,000				107,000
Term Loan With Related Hedging Instrument
Debt Instrument [Line Items]
Total principal balance					50,000				50,000
Terrm Loan Without Related Hedging Instrument
Debt Instrument [Line Items]
Total principal balance					$ 100,000				50,000
LIBOR | Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					1.40%
LIBOR | Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					2.00%
LIBOR | Term Loan With Related Hedging Instrument | Minimum
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					1.35%
LIBOR | Term Loan With Related Hedging Instrument | Maximum
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					1.95%
LIBOR | Terrm Loan Without Related Hedging Instrument | Minimum
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					1.35%
LIBOR | Terrm Loan Without Related Hedging Instrument | Maximum
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					1.95%
North Point Center | Note 5
Debt Instrument [Line Items]
Total principal balance					$ 0				643
North Point Center | Note 5 | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					2.00%
North Point Center | Notes 1
Debt Instrument [Line Items]
Total principal balance					$ 9,571				9,776
Stated interest rate					6.45%
North Point Center | Notes 2
Debt Instrument [Line Items]
Total principal balance					$ 2,459				2,564
Stated interest rate					7.25%
Harrisonburg Regal
Debt Instrument [Line Items]
Total principal balance					$ 0				3,256
Stated interest rate					6.06%
Commonwealth of Virginia | Chesapeake
Debt Instrument [Line Items]
Total principal balance					$ 0				4,933
Commonwealth of Virginia | LIBOR | Chesapeake
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					1.90%
Sandbridge Commons
Debt Instrument [Line Items]
Total principal balance					$ 8,468				9,376
Sandbridge Commons | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					1.75%
Columbus Village | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate			2.00%
Columbus Village | Notes 1
Debt Instrument [Line Items]
Total principal balance					$ 6,080				6,258
Columbus Village | Notes 1 | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					2.00%
Columbus Village | Notes 2
Debt Instrument [Line Items]
Total principal balance					$ 2,218				2,266
Columbus Village | Notes 2 | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					2.00%
Johns Hopkins Village
Debt Instrument [Line Items]
Total principal balance					$ 46,698				43,841
Johns Hopkins Village | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate		1.90%			1.90%
Lightfoot Marketplace
Debt Instrument [Line Items]
Total principal balance					$ 10,500	$ 10,500			12,194
Lightfoot Marketplace | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					1.75%
Harding Place
Debt Instrument [Line Items]
Total principal balance					$ 3,874				0
Harding Place | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					2.95%
Town Center Phase VI
Debt Instrument [Line Items]
Total principal balance					$ 1,505				0
Town Center Phase VI | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					3.50%
Southgate Square
Debt Instrument [Line Items]
Total principal balance					$ 20,708				21,150
Southgate Square | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					2.00%
249 Central Park Retail
Debt Instrument [Line Items]
Total principal balance					$ 16,851				17,076
249 Central Park Retail | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					1.95%
Fountain Plaza Retail
Debt Instrument [Line Items]
Total principal balance					$ 10,145				10,281
Fountain Plaza Retail | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					1.95%
South Retail
Debt Instrument [Line Items]
Total principal balance					$ 7,394				7,493
South Retail | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate					1.95%
4525 Main Street
Debt Instrument [Line Items]
Total principal balance					$ 32,034				32,034
Stated interest rate					3.25%
Encore Apartments
Debt Instrument [Line Items]
Total principal balance					$ 24,966				24,966
Stated interest rate					3.25%
Hanbury Village
Debt Instrument [Line Items]
Total principal balance					$ 19,503				20,709
Stated interest rate					3.78%			3.78%
Socastee Commons
Debt Instrument [Line Items]
Total principal balance					$ 4,771				4,866
Stated interest rate					4.57%					4.57%
Smith’s Landing
Debt Instrument [Line Items]
Total principal balance					$ 19,764				20,511
Stated interest rate					4.05%						4.05%
Liberty Apartments
Debt Instrument [Line Items]
Total principal balance					$ 14,694				20,005
Stated interest rate					5.66%
The Cosmopolitan
Debt Instrument [Line Items]
Total principal balance					$ 45,209				$ 45,884
Stated interest rate					3.35%		3.35%		3.75%
Subsequent Event | Sandbridge Commons
Debt Instrument [Line Items]
Debt assumed, term				5 years
Subsequent Event | Sandbridge Commons | LIBOR
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate	1.75%