Schedule III - Real Estate and Accumulated Depreciation (Details)		12 Months Ended
		Dec. 31, 2020 USD ($) property		Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Gross Leasable Area | property		8,084,797
Initial cost to the Company, Land		$ 285,607,000
Initial cost to the Company, Building and Improvements		892,766,000
Subsequent cost capitalized	[1]	349,105,000
Gross carrying amount of Land		284,694,000
Gross carrying amount of building and improvements		1,242,784,000
SEC Schedule III, Real Estate, Gross, Total		1,527,478,000	[2]	$ 1,515,206,000	$ 1,508,682,000	$ 1,534,599,000
Accumulated Depreciation		$ 428,569,000		$ 389,861,000	$ 361,969,000	$ 341,943,000
Academy Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2001
Percent Owned		100.00%
Gross Leasable Area | property		137,415
Initial cost to the Company, Land		$ 2,406,000
Initial cost to the Company, Building and Improvements		9,623,000
Subsequent cost capitalized	[1]	6,107,000
Gross carrying amount of Land		2,406,000
Gross carrying amount of building and improvements		15,730,000
SEC Schedule III, Real Estate, Gross, Total		18,136,000
Accumulated Depreciation		$ 6,651,000
Academy Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1965
Academy Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2013
Big Y Shopping Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2013
Percent Owned		100.00%
Year built/Year last renovated		2007
Gross Leasable Area | property		101,105
Initial cost to the Company, Land		$ 11,272,000
Initial cost to the Company, Building and Improvements		23,395,000
Subsequent cost capitalized	[1]	361,000
Gross carrying amount of Land		10,268,000
Gross carrying amount of building and improvements		24,760,000
SEC Schedule III, Real Estate, Gross, Total		35,028,000
Accumulated Depreciation		$ 5,560,000
Camp Hill [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2002
Percent Owned		100.00%
Gross Leasable Area | property		430,198
Initial cost to the Company, Land		$ 4,460,000
Initial cost to the Company, Building and Improvements		17,857,000
Subsequent cost capitalized	[1]	40,626,000
Gross carrying amount of Land		4,093,000
Gross carrying amount of building and improvements		58,850,000
SEC Schedule III, Real Estate, Gross, Total		62,943,000
Accumulated Depreciation		$ 24,270,000
Camp Hill [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1958
Camp Hill [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2005
Carmans Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2007
Percent Owned		100.00%
Gross Leasable Area | property		195,485
Initial cost to the Company, Land		$ 8,539,000
Initial cost to the Company, Building and Improvements		35,804,000
Subsequent cost capitalized	[1]	18,641,000
Gross carrying amount of Land		8,421,000
Gross carrying amount of building and improvements		54,563,000
SEC Schedule III, Real Estate, Gross, Total		62,984,000
Accumulated Depreciation		$ 17,896,000
Carmans Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1954
Carmans Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2007
Christina Crossing [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2017
Percent Owned		100.00%
Year built/Year last renovated		2008
Gross Leasable Area | property		119,446
Initial cost to the Company, Land		$ 4,341,000
Initial cost to the Company, Building and Improvements		23,227,000
Subsequent cost capitalized	[1]	1,603,000
Gross carrying amount of Land		4,341,000
Gross carrying amount of building and improvements		24,830,000
SEC Schedule III, Real Estate, Gross, Total		29,171,000
Accumulated Depreciation		$ 3,595,000
Coliseum Marketplace [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2005
Percent Owned		100.00%
Gross Leasable Area | property		106,648
Initial cost to the Company, Land		$ 2,924,000
Initial cost to the Company, Building and Improvements		14,416,000
Subsequent cost capitalized	[1]	5,629,000
Gross carrying amount of Land		3,586,000
Gross carrying amount of building and improvements		19,383,000
SEC Schedule III, Real Estate, Gross, Total		22,969,000
Accumulated Depreciation		$ 8,465,000
Coliseum Marketplace [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1987
Coliseum Marketplace [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2012
Colonial Commons [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2011
Percent Owned		100.00%
Gross Leasable Area | property		410,432
Initial cost to the Company, Land		$ 9,367,000
Initial cost to the Company, Building and Improvements		37,496,000
Subsequent cost capitalized	[1]	7,846,000
Gross carrying amount of Land		9,367,000
Gross carrying amount of building and improvements		45,342,000
SEC Schedule III, Real Estate, Gross, Total		54,709,000
Accumulated Depreciation		$ 16,580,000
Colonial Commons [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2011
Colonial Commons [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2013
Crossroads II [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2008
Percent Owned		60.00%
Year built/Year last renovated		2009
Gross Leasable Area | property		133,717
Initial cost to the Company, Land		$ 15,383,000
Subsequent cost capitalized	[1]	29,734,000
Gross carrying amount of Land		17,671,000
Gross carrying amount of building and improvements		27,446,000
SEC Schedule III, Real Estate, Gross, Total		45,117,000
Accumulated Depreciation		$ 8,147,000
East River Park [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2015
Percent Owned		100.00%
Gross Leasable Area | property		150,038
Initial cost to the Company, Land		$ 9,143,000
Initial cost to the Company, Building and Improvements		30,893,000
Subsequent cost capitalized	[1]	7,514,000
Gross carrying amount of Land		9,398,000
Gross carrying amount of building and improvements		38,152,000
SEC Schedule III, Real Estate, Gross, Total		47,550,000
Accumulated Depreciation		$ 6,558,000
East River Park [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1946
East River Park [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1996
Elmhurst Square [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2006
Percent Owned		100.00%
Gross Leasable Area | property		66,254
Initial cost to the Company, Land		$ 1,371,000
Initial cost to the Company, Building and Improvements		5,994,000
Subsequent cost capitalized	[1]	1,251,000
Gross carrying amount of Land		1,371,000
Gross carrying amount of building and improvements		7,245,000
SEC Schedule III, Real Estate, Gross, Total		8,616,000
Accumulated Depreciation		$ 2,668,000
Elmhurst Square [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1961
Elmhurst Square [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1983
Fairview Commons [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2007
Percent Owned		100.00%
Gross Leasable Area | property		52,964
Initial cost to the Company, Land		$ 858,000
Initial cost to the Company, Building and Improvements		3,568,000
Subsequent cost capitalized	[1]	452,000
Gross carrying amount of Land		858,000
Gross carrying amount of building and improvements		4,020,000
SEC Schedule III, Real Estate, Gross, Total		4,878,000
Accumulated Depreciation		$ 1,470,000
Fairview Commons [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1976
Fairview Commons [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2003
Fieldstone Marketplace [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Percent Owned		100.00%
Gross Leasable Area | property		150,123
Initial cost to the Company, Land		$ 5,229,000
Initial cost to the Company, Building and Improvements		21,440,000
Subsequent cost capitalized	[1]	3,386,000
Gross carrying amount of Land		5,167,000
Gross carrying amount of building and improvements		24,888,000
SEC Schedule III, Real Estate, Gross, Total		30,055,000
Accumulated Depreciation		$ 10,740,000
Fieldstone Marketplace [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2005
Year built/Year last renovated		1988
Fieldstone Marketplace [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2012
Year built/Year last renovated		2003
Fishtown Crossing [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2001
Percent Owned		100.00%
Year built/Year last renovated		1988
Gross Leasable Area | property		127,265
Initial cost to the Company, Land		$ 2,942,000
Initial cost to the Company, Building and Improvements		11,769,000
Subsequent cost capitalized	[1]	9,676,000
Gross carrying amount of Land		2,843,000
Gross carrying amount of building and improvements		21,544,000
SEC Schedule III, Real Estate, Gross, Total		24,387,000
Accumulated Depreciation		$ 5,417,000
Franklin Village Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Percent Owned	[3]	100.00%
Gross Leasable Area | property	[3]	305,937
Initial cost to the Company, Land	[3]	$ 14,270,000
Initial cost to the Company, Building and Improvements	[3]	61,915,000
Subsequent cost capitalized	[1],[3]	6,494,000
Gross carrying amount of Land	[3]	14,681,000
Gross carrying amount of building and improvements	[3]	67,998,000
SEC Schedule III, Real Estate, Gross, Total	[3]	82,679,000
Accumulated Depreciation	[3]	$ 19,215,000
Franklin Village Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired	[3]	2004
Year built/Year last renovated	[3]	1987
Franklin Village Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired	[3]	2012
Year built/Year last renovated	[3]	2005
General Booth Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2005
Percent Owned		100.00%
Year built/Year last renovated		1985
Gross Leasable Area | property		71,639
Initial cost to the Company, Land		$ 1,935,000
Initial cost to the Company, Building and Improvements		9,493,000
Subsequent cost capitalized	[1]	(132,000)
Gross carrying amount of Land		1,935,000
Gross carrying amount of building and improvements		9,361,000
SEC Schedule III, Real Estate, Gross, Total		11,296,000
Accumulated Depreciation		$ 3,522,000
Girard Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2019
Percent Owned		100.00%
Gross Leasable Area | property		35,688
Initial cost to the Company, Land		$ 4,685,000
Initial cost to the Company, Building and Improvements		4,648,000
Subsequent cost capitalized	[1]	52,000
Gross carrying amount of Land		4,685,000
Gross carrying amount of building and improvements		4,700,000
SEC Schedule III, Real Estate, Gross, Total		9,385,000
Accumulated Depreciation		$ 405,000
Girard Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1950
Girard Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2010
Gold Star Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2006
Percent Owned		100.00%
Year built/Year last renovated		1988
Gross Leasable Area | property		71,720
Initial cost to the Company, Land		$ 1,644,000
Initial cost to the Company, Building and Improvements		6,519,000
Subsequent cost capitalized	[1]	755,000
Gross carrying amount of Land		1,644,000
Gross carrying amount of building and improvements		7,274,000
SEC Schedule III, Real Estate, Gross, Total		8,918,000
Accumulated Depreciation		$ 3,409,000
Golden Triangle [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2003
Percent Owned		100.00%
Gross Leasable Area | property		202,790
Initial cost to the Company, Land		$ 2,320,000
Initial cost to the Company, Building and Improvements		9,713,000
Subsequent cost capitalized	[1]	12,824,000
Gross carrying amount of Land		2,320,000
Gross carrying amount of building and improvements		22,537,000
SEC Schedule III, Real Estate, Gross, Total		24,857,000
Accumulated Depreciation		$ 10,288,000
Golden Triangle [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1960
Golden Triangle [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2005
Groton Shopping Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2007
Percent Owned		100.00%
Year built/Year last renovated		1969
Gross Leasable Area | property		130,264
Initial cost to the Company, Land		$ 3,070,000
Initial cost to the Company, Building and Improvements		12,320,000
Subsequent cost capitalized	[1]	8,552,000
Gross carrying amount of Land		3,113,000
Gross carrying amount of building and improvements		20,829,000
SEC Schedule III, Real Estate, Gross, Total		23,942,000
Accumulated Depreciation		$ 6,453,000
Halifax Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2003
Percent Owned		100.00%
Year built/Year last renovated		1994
Gross Leasable Area | property		51,510
Initial cost to the Company, Land		$ 1,412,000
Initial cost to the Company, Building and Improvements		5,799,000
Subsequent cost capitalized	[1]	562,000
Gross carrying amount of Land		1,347,000
Gross carrying amount of building and improvements		6,426,000
SEC Schedule III, Real Estate, Gross, Total		7,773,000
Accumulated Depreciation		$ 3,059,000
Hamburg Square [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2004
Percent Owned		100.00%
Gross Leasable Area | property		102,058
Initial cost to the Company, Land		$ 1,153,000
Initial cost to the Company, Building and Improvements		4,678,000
Subsequent cost capitalized	[1]	6,332,000
Gross carrying amount of Land		1,153,000
Gross carrying amount of building and improvements		11,010,000
SEC Schedule III, Real Estate, Gross, Total		12,163,000
Accumulated Depreciation		$ 4,210,000
Hamburg Square [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1993
Hamburg Square [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2010
Jordan Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2005
Percent Owned		100.00%
Gross Leasable Area | property		177,504
Initial cost to the Company, Land		$ 4,291,000
Initial cost to the Company, Building and Improvements		21,176,000
Subsequent cost capitalized	[1]	1,122,000
Gross carrying amount of Land		4,291,000
Gross carrying amount of building and improvements		22,298,000
SEC Schedule III, Real Estate, Gross, Total		26,589,000
Accumulated Depreciation		$ 8,744,000
Jordan Lane [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1969
Jordan Lane [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1991
Kempsville Crossing [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2005
Percent Owned		100.00%
Gross Leasable Area | property		79,512
Initial cost to the Company, Land		$ 2,207,000
Initial cost to the Company, Building and Improvements		11,000,000
Subsequent cost capitalized	[1]	(2,754,000)
Gross carrying amount of Land		2,207,000
Gross carrying amount of building and improvements		8,246,000
SEC Schedule III, Real Estate, Gross, Total		10,453,000
Accumulated Depreciation		$ 3,399,000
Kempsville Crossing [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1985
Kempsville Crossing [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2013
Kings Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2007
Percent Owned		100.00%
Gross Leasable Area | property		168,243
Initial cost to the Company, Land		$ 2,413,000
Initial cost to the Company, Building and Improvements		12,604,000
Subsequent cost capitalized	[1]	1,684,000
Gross carrying amount of Land		2,408,000
Gross carrying amount of building and improvements		14,293,000
SEC Schedule III, Real Estate, Gross, Total		16,701,000
Accumulated Depreciation		$ 4,489,000
Kings Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1970
Kings Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1994
Lawndale Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2015
Percent Owned		100.00%
Year built/Year last renovated		1998
Gross Leasable Area | property		92,773
Initial cost to the Company, Land		$ 3,635,000
Initial cost to the Company, Building and Improvements		21,854,000
Subsequent cost capitalized	[1]	1,091,000
Gross carrying amount of Land		3,635,000
Gross carrying amount of building and improvements		22,945,000
SEC Schedule III, Real Estate, Gross, Total		26,580,000
Accumulated Depreciation		$ 4,783,000
Meadows Marketplace [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Percent Owned		100.00%
Year built/Year last renovated		2005
Gross Leasable Area | property		91,518
Initial cost to the Company, Land		$ 1,914,000
Subsequent cost capitalized	[1]	11,959,000
Gross carrying amount of Land		1,914,000
Gross carrying amount of building and improvements		11,959,000
SEC Schedule III, Real Estate, Gross, Total		13,873,000
Accumulated Depreciation		$ 4,324,000
Meadows Marketplace [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2004
Meadows Marketplace [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2012
Newport Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2003
Percent Owned		100.00%
Year built/Year last renovated		1996
Gross Leasable Area | property		64,489
Initial cost to the Company, Land		$ 1,721,000
Initial cost to the Company, Building and Improvements		7,758,000
Subsequent cost capitalized	[1]	586,000
Gross carrying amount of Land		1,682,000
Gross carrying amount of building and improvements		8,383,000
SEC Schedule III, Real Estate, Gross, Total		10,065,000
Accumulated Depreciation		$ 3,948,000
New London Mall [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2009
Percent Owned		100.00%
Gross Leasable Area | property		259,566
Initial cost to the Company, Land		$ 14,891,000
Initial cost to the Company, Building and Improvements		24,967,000
Subsequent cost capitalized	[1]	4,797,000
Gross carrying amount of Land		8,807,000
Gross carrying amount of building and improvements		35,848,000
SEC Schedule III, Real Estate, Gross, Total		44,655,000
Accumulated Depreciation		$ 15,186,000
New London Mall [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1967
New London Mall [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1997
Northside Commons [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2008
Percent Owned		100.00%
Year built/Year last renovated		2009
Gross Leasable Area | property		69,136
Initial cost to the Company, Land		$ 3,332,000
Subsequent cost capitalized	[1]	10,108,000
Gross carrying amount of Land		3,379,000
Gross carrying amount of building and improvements		10,061,000
SEC Schedule III, Real Estate, Gross, Total		13,440,000
Accumulated Depreciation		$ 2,863,000
Norwood Shopping Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2006
Percent Owned		100.00%
Gross Leasable Area | property		87,406
Initial cost to the Company, Land		$ 1,874,000
Initial cost to the Company, Building and Improvements		8,453,000
Subsequent cost capitalized	[1]	1,017,000
Gross carrying amount of Land		1,874,000
Gross carrying amount of building and improvements		9,470,000
SEC Schedule III, Real Estate, Gross, Total		11,344,000
Accumulated Depreciation		$ 3,447,000
Norwood Shopping Center [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1965
Norwood Shopping Center [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2013
Oak Ridge Shopping Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2006
Percent Owned		100.00%
Year built/Year last renovated		2000
Gross Leasable Area | property		38,700
Initial cost to the Company, Land		$ 960,000
Initial cost to the Company, Building and Improvements		4,254,000
Subsequent cost capitalized	[1]	471,000
Gross carrying amount of Land		960,000
Gross carrying amount of building and improvements		4,725,000
SEC Schedule III, Real Estate, Gross, Total		5,685,000
Accumulated Depreciation		$ 1,878,000
Oakland Commons [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2007
Percent Owned		100.00%
Gross Leasable Area | property		90,100
Initial cost to the Company, Land		$ 2,504,000
Initial cost to the Company, Building and Improvements		15,662,000
Subsequent cost capitalized	[1]	(344,000)
Gross carrying amount of Land		2,504,000
Gross carrying amount of building and improvements		15,318,000
SEC Schedule III, Real Estate, Gross, Total		17,822,000
Accumulated Depreciation		$ 5,904,000
Oakland Commons [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1962
Oakland Commons [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2013
Oakland Mills [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2005
Percent Owned		100.00%
Gross Leasable Area | property		57,008
Initial cost to the Company, Land		$ 1,611,000
Initial cost to the Company, Building and Improvements		6,292,000
Subsequent cost capitalized	[1]	1,088,000
Gross carrying amount of Land		1,530,000
Gross carrying amount of building and improvements		7,461,000
SEC Schedule III, Real Estate, Gross, Total		8,991,000
Accumulated Depreciation		$ 3,088,000
Oakland Mills [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1960
Oakland Mills [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2004
Palmyra Shopping Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2005
Percent Owned		100.00%
Gross Leasable Area | property		111,051
Initial cost to the Company, Land		$ 1,488,000
Initial cost to the Company, Building and Improvements		6,566,000
Subsequent cost capitalized	[1]	2,082,000
Gross carrying amount of Land		1,488,000
Gross carrying amount of building and improvements		8,648,000
SEC Schedule III, Real Estate, Gross, Total		10,136,000
Accumulated Depreciation		$ 3,731,000
Palmyra Shopping Center [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1960
Palmyra Shopping Center [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2012
Pine Grove Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2003
Percent Owned		100.00%
Gross Leasable Area | property		79,306
Initial cost to the Company, Land		$ 2,010,000
Initial cost to the Company, Building and Improvements		6,489,000
Subsequent cost capitalized	[1]	579,000
Gross carrying amount of Land		1,622,000
Gross carrying amount of building and improvements		7,456,000
SEC Schedule III, Real Estate, Gross, Total		9,078,000
Accumulated Depreciation		$ 3,386,000
Pine Grove Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2001
Pine Grove Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2002
Quartermaster Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2014
Percent Owned		100.00%
Year built/Year last renovated		2004
Gross Leasable Area | property		456,602
Initial cost to the Company, Land		$ 37,031,000
Initial cost to the Company, Building and Improvements		54,210,000
Subsequent cost capitalized	[1]	3,548,000
Gross carrying amount of Land		37,031,000
Gross carrying amount of building and improvements		57,758,000
SEC Schedule III, Real Estate, Gross, Total		94,789,000
Accumulated Depreciation		$ 13,019,000
River View Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2003
Percent Owned		100.00%
Gross Leasable Area | property		113,922
Initial cost to the Company, Land		$ 9,718,000
Initial cost to the Company, Building and Improvements		40,356,000
Subsequent cost capitalized	[1]	9,598,000
Gross carrying amount of Land		10,872,000
Gross carrying amount of building and improvements		48,800,000
SEC Schedule III, Real Estate, Gross, Total		59,672,000
Accumulated Depreciation		$ 20,002,000
River View Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1991
River View Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1998
San Souci Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2009
Percent Owned		40.00%
Gross Leasable Area | property		264,134
Initial cost to the Company, Land		$ 14,849,000
Initial cost to the Company, Building and Improvements		18,445,000
Subsequent cost capitalized	[1]	5,182,000
Gross carrying amount of Land		13,406,000
Gross carrying amount of building and improvements		25,070,000
SEC Schedule III, Real Estate, Gross, Total		38,476,000
Accumulated Depreciation		$ 13,092,000
San Souci Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1985
San Souci Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1997
Senator Square [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2018
Percent Owned		100.00%
Gross Leasable Area | property		42,941
Initial cost to the Company, Building and Improvements		$ 5,327,000
Subsequent cost capitalized	[1]	2,485,000
Gross carrying amount of building and improvements		7,812,000
SEC Schedule III, Real Estate, Gross, Total		7,812,000
Accumulated Depreciation		$ 1,145,000
Senator Square [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1946
Senator Square [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2005
Shoppes at Arts District [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2016
Percent Owned		100.00%
Year built/Year last renovated		2011
Gross Leasable Area | property		35,676
Initial cost to the Company, Land		$ 2,247,000
Initial cost to the Company, Building and Improvements		18,616,000
Subsequent cost capitalized	[1]	75,000
Gross carrying amount of Land		2,247,000
Gross carrying amount of building and improvements		18,691,000
SEC Schedule III, Real Estate, Gross, Total		20,938,000
Accumulated Depreciation		$ 3,338,000
South Philadelphia [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2003
Percent Owned		100.00%
Gross Leasable Area | property		193,085
Initial cost to the Company, Land		$ 8,222,000
Initial cost to the Company, Building and Improvements		36,314,000
Subsequent cost capitalized	[1]	17,210,000
Gross carrying amount of Land		10,363,000
Gross carrying amount of building and improvements		51,383,000
SEC Schedule III, Real Estate, Gross, Total		61,746,000
Accumulated Depreciation		$ 23,388,000
South Philadelphia [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1950
South Philadelphia [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2003
Southington Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2003
Percent Owned		100.00%
Gross Leasable Area | property		155,842
Initial cost to the Company, Building and Improvements		$ 11,834,000
Subsequent cost capitalized	[1]	1,704,000
Gross carrying amount of building and improvements		13,538,000
SEC Schedule III, Real Estate, Gross, Total		13,538,000
Accumulated Depreciation		$ 5,429,000
Southington Center [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1972
Southington Center [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2000
Swede Square [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2003
Percent Owned		100.00%
Gross Leasable Area | property		100,809
Initial cost to the Company, Land		$ 2,268,000
Initial cost to the Company, Building and Improvements		6,232,000
Subsequent cost capitalized	[1]	8,254,000
Gross carrying amount of Land		2,272,000
Gross carrying amount of building and improvements		14,482,000
SEC Schedule III, Real Estate, Gross, Total		16,754,000
Accumulated Depreciation		$ 6,309,000
Swede Square [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1980
Swede Square [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2012
The Brickyard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2004
Percent Owned		100.00%
Gross Leasable Area | property		227,598
Initial cost to the Company, Land		$ 7,632,000
Initial cost to the Company, Building and Improvements		29,308,000
Subsequent cost capitalized	[1]	4,821,000
Gross carrying amount of Land		7,648,000
Gross carrying amount of building and improvements		34,113,000
SEC Schedule III, Real Estate, Gross, Total		41,761,000
Accumulated Depreciation		$ 12,923,000
The Brickyard [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1990
The Brickyard [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2012
The Point [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2000
Percent Owned		100.00%
Gross Leasable Area | property		262,072
Initial cost to the Company, Land		$ 2,700,000
Initial cost to the Company, Building and Improvements		10,800,000
Subsequent cost capitalized	[1]	19,534,000
Gross carrying amount of Land		2,996,000
Gross carrying amount of building and improvements		30,038,000
SEC Schedule III, Real Estate, Gross, Total		33,034,000
Accumulated Depreciation		$ 13,507,000
The Point [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1972
The Point [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2012
The Shops at Bloomfield Station [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2016
Percent Owned		100.00%
Year built/Year last renovated		2015
Gross Leasable Area | property		63,844
Initial cost to the Company, Land		$ 625,000
Initial cost to the Company, Building and Improvements		17,674,000
Subsequent cost capitalized	[1]	393,000
Gross carrying amount of Land		625,000
Gross carrying amount of building and improvements		18,067,000
SEC Schedule III, Real Estate, Gross, Total		18,692,000
Accumulated Depreciation		$ 3,097,000
The Shops at Suffolk Downs [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2005
Percent Owned		100.00%
Gross Leasable Area | property		121,187
Initial cost to the Company, Land		$ 7,580,000
Initial cost to the Company, Building and Improvements		11,089,000
Subsequent cost capitalized	[1]	10,547,000
Gross carrying amount of Land		7,580,000
Gross carrying amount of building and improvements		21,636,000
SEC Schedule III, Real Estate, Gross, Total		29,216,000
Accumulated Depreciation		$ 7,942,000
The Shops at Suffolk Downs [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2005
The Shops at Suffolk Downs [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2011
Timpany Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2007
Percent Owned		100.00%
Gross Leasable Area | property		182,799
Initial cost to the Company, Land		$ 3,412,000
Initial cost to the Company, Building and Improvements		19,240,000
Subsequent cost capitalized	[1]	2,366,000
Gross carrying amount of Land		3,368,000
Gross carrying amount of building and improvements		21,650,000
SEC Schedule III, Real Estate, Gross, Total		25,018,000
Accumulated Depreciation		$ 7,006,000
Timpany Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1970
Timpany Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1989
Trexler Mall [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2005
Percent Owned		100.00%
Gross Leasable Area | property		336,687
Initial cost to the Company, Land		$ 6,932,000
Initial cost to the Company, Building and Improvements		32,815,000
Subsequent cost capitalized	[1]	13,691,000
Gross carrying amount of Land		6,932,000
Gross carrying amount of building and improvements		46,506,000
SEC Schedule III, Real Estate, Gross, Total		53,438,000
Accumulated Depreciation		$ 16,945,000
Trexler Mall [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1973
Trexler Mall [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2013
Trexlertown Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2006
Percent Owned		100.00%
Gross Leasable Area | property		325,171
Initial cost to the Company, Land		$ 13,349,000
Initial cost to the Company, Building and Improvements		23,867,000
Subsequent cost capitalized	[1]	31,032,000
Gross carrying amount of Land		15,674,000
Gross carrying amount of building and improvements		52,574,000
SEC Schedule III, Real Estate, Gross, Total		68,248,000
Accumulated Depreciation		$ 14,866,000
Trexlertown Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1990
Trexlertown Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2011
Valley Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2003
Percent Owned		100.00%
Gross Leasable Area | property		190,939
Initial cost to the Company, Land		$ 1,950,000
Initial cost to the Company, Building and Improvements		7,766,000
Subsequent cost capitalized	[1]	1,903,000
Gross carrying amount of Land		1,950,000
Gross carrying amount of building and improvements		9,669,000
SEC Schedule III, Real Estate, Gross, Total		11,619,000
Accumulated Depreciation		$ 4,490,000
Valley Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1975
Valley Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1994
Washington Center Shoppes [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2001
Percent Owned		100.00%
Gross Leasable Area | property		157,300
Initial cost to the Company, Land		$ 2,061,000
Initial cost to the Company, Building and Improvements		7,314,000
Subsequent cost capitalized	[1]	6,891,000
Gross carrying amount of Land		2,000,000
Gross carrying amount of building and improvements		14,266,000
SEC Schedule III, Real Estate, Gross, Total		16,266,000
Accumulated Depreciation		$ 6,315,000
Washington Center Shoppes [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1979
Washington Center Shoppes [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1995
Webster Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2007
Percent Owned		100.00%
Gross Leasable Area | property		98,984
Initial cost to the Company, Land		$ 3,551,000
Initial cost to the Company, Building and Improvements		18,412,000
Subsequent cost capitalized	[1]	4,035,000
Gross carrying amount of Land		4,082,000
Gross carrying amount of building and improvements		21,916,000
SEC Schedule III, Real Estate, Gross, Total		25,998,000
Accumulated Depreciation		$ 7,353,000
Webster Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1960
Webster Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2004
Yorktowne Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year acquired		2007
Percent Owned		100.00%
Gross Leasable Area | property		136,197
Initial cost to the Company, Land		$ 5,940,000
Initial cost to the Company, Building and Improvements		25,505,000
Subsequent cost capitalized	[1]	2,560,000
Gross carrying amount of Land		5,801,000
Gross carrying amount of building and improvements		28,204,000
SEC Schedule III, Real Estate, Gross, Total		34,005,000
Accumulated Depreciation		$ 10,323,000
Yorktowne Plaza [Member] | Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		1970
Yorktowne Plaza [Member] | Maximum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year built/Year last renovated		2000
Other [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Percent Owned		100.00%
Initial cost to the Company, Land		$ 1,965,000
Subsequent cost capitalized	[1]	1,525,000
Gross carrying amount of Land		878,000
Gross carrying amount of building and improvements		2,612,000
SEC Schedule III, Real Estate, Gross, Total		3,490,000
Accumulated Depreciation		$ 332,000

[1] Negative amounts represent write-offs of fully depreciated assets.

[2] At December 31, 2020, the aggregate cost for federal income tax purposes was approximately $25.6 million greater than the Company's recorded values.

[3] Amount of encumbrance totals $45.6 million at December 31, 2020.