Loans Payable - Additional Information (Details)

v3.10.0.1

Loans Payable - Additional Information (Details)																														1 Months Ended		2 Months Ended	12 Months Ended
	Jan. 11, 2019 USD ($)	Dec. 15, 2018 USD ($)	Dec. 11, 2018 USD ($)	Nov. 21, 2018 USD ($)	Nov. 05, 2018 USD ($)	Oct. 22, 2018 USD ($)	Oct. 15, 2018 USD ($)	Sep. 27, 2018 USD ($)	Jul. 15, 2018 USD ($)	Jun. 28, 2018 USD ($)	Jun. 19, 2018 USD ($)	Jun. 15, 2018	May 14, 2018 USD ($)	Mar. 11, 2018 USD ($)	Jan. 18, 2018 USD ($)	Jan. 10, 2018	Dec. 21, 2017 USD ($)	Dec. 12, 2017 USD ($)	Oct. 07, 2017 USD ($)	Oct. 06, 2017	Aug. 29, 2017 USD ($)	May 03, 2017 USD ($)	May 01, 2017 USD ($)	Mar. 22, 2017 USD ($)	Dec. 21, 2016	Dec. 20, 2016	Apr. 28, 2016 USD ($) shares	Apr. 12, 2016 USD ($)	Apr. 08, 2016 USD ($) $ / shares shares	Sep. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Feb. 27, 2019 USD ($)	Dec. 31, 2018 USD ($) parcel property shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($)	Jan. 29, 2019 USD ($)	Jan. 15, 2019 USD ($)	Oct. 05, 2018 USD ($)	Aug. 07, 2018 USD ($)	Jul. 01, 2018 USD ($)	May 03, 2018 USD ($)	Apr. 01, 2018 USD ($)	Mar. 31, 2018 USD ($)	Mar. 02, 2018 USD ($)	Dec. 06, 2017 USD ($)	Dec. 05, 2017 USD ($)	Sep. 16, 2017 USD ($)	Jul. 18, 2017 USD ($)	Jun. 14, 2017 USD ($)	Dec. 07, 2016 USD ($)	Aug. 15, 2016 USD ($)	May 29, 2015 USD ($)
Debt Instrument [Line Items]
Loans payable, net																																	$ 360,117,000	$ 307,375,000
Conversion of senior convertible debt into Common Stock																																	0	31,000	$ 1,600,000
Long-term debt maturities in 2019																																	88,036,000
Loan principal payments																																	28,856,000	18,227,000	29,163,000
Long-term debt maturities in 2019 fully amortizing through regularly scheduled payments																																	1,440,000
Net cash provided by operating activities																																	22,002,000	23,818,000	11,100,000
Cash received from disposal of properties																																	$ 3,530,000	2,416,000	$ 0
Number of undeveloped land parcels | parcel																																	6
Ladson Crossing, Lake Greenwood and South Park [Member]
Debt Instrument [Line Items]
Loans payable, net																																	$ 7,600,000
Revere Loan [Member]
Debt Instrument [Line Items]
Debt periodic payment																					$ 25,000		$ 450,000								$ 167,000
Loans payable, net																							7,450,000
Debt extension fee																							$ 140,000
Chesapeake Square [Member]
Debt Instrument [Line Items]
Debt periodic payment																																	$ 23,857
Debt interest rate																																	4.70%
Loans payable, net																																	$ 4,434,000	4,507,000
Perimeter Square [Member]
Debt Instrument [Line Items]
Debt interest rate																																	5.50%																5.50%
Loans payable, net																																	$ 6,250,000	5,382,000															$ 4,500,000
Perimeter Square Construction Loan [Member]
Debt Instrument [Line Items]
Debt interest rate																																	6.00%					6.00%
Loans payable, net																																	$ 247,000	0
Riversedge North [Member]
Debt Instrument [Line Items]
Debt periodic payment			$ 11,436																														$ 11,436
Debt interest rate			5.77%																														5.77%
Loans payable, net			$ 1,800,000																														$ 1,800,000	863,000
Shoppes At Tj Maxx [Member]
Debt Instrument [Line Items]
Debt periodic payment																																	$ 33,880
Debt interest rate																																	3.88%
Loans payable, net																																	$ 5,539,000	5,727,000
Lumber River Plaza [Member]
Debt Instrument [Line Items]
Debt spread over variable basis percentage																										2.95%
Harbor Point [Member]
Debt Instrument [Line Items]
Debt periodic payment																																	$ 11,024
Debt interest rate																																	5.85%
Rivergate Shopping Center [Member]
Debt Instrument [Line Items]
Debt spread over variable basis percentage																									2.95%
Debt periodic payment																																		1,520,000
Folly Road [Member]
Debt Instrument [Line Items]
Debt periodic payment																																	$ 32,827
Debt interest rate																								4.00%									4.00%
Loans payable, net																								$ 8,570,000									$ 6,073,000	6,181,000
Columbia Fire House Construction Loan [Member]
Debt Instrument [Line Items]
Term of credit facility																						20 years
Debt periodic payment																																	$ 25,452
Debt interest rate																						4.00%											4.00%
Loans payable, net																						$ 4,300,000											$ 4,189,000	3,421,000
Walnut Hill Plaza [Member]
Debt Instrument [Line Items]
Term of credit facility																					20 years
Debt periodic payment																					$ 26,850												$ 26,850
Debt interest rate																					5.50%												5.50%
Loans payable, net																					$ 3,900,000												$ 3,868,000	3,903,000														$ 3,390,000
Monarch Bank Line Of Credit [Member]
Debt Instrument [Line Items]
Maximum line of credit borrowing capacity																																															$ 3,000,000
Debt periodic payment																		$ 7,340
Debt interest rate																		4.85%
Loans payable, net																		$ 1,270,000
Columbia Fire Station [Member]
Debt Instrument [Line Items]
Debt periodic payment																																		262,000
Loans payable, net																						$ 262,000
Rivergate [Member]
Debt Instrument [Line Items]
Debt periodic payment																																	144,823
Loans payable, net																																	22,117,000	22,689,000
Shoppes At Eagle Harbor [Member]
Debt Instrument [Line Items]
Term of credit facility														5 years
Debt periodic payment														$ 26,528																			$ 26,528
Debt interest rate														5.10%																			5.10%
Loans payable, net														$ 3,320,000																			$ 0	3,341,000
LIBOR | Monarch Bank Line Of Credit [Member]
Debt Instrument [Line Items]
Debt spread over variable basis percentage							3.00%					3.50%				3.00%
Debt floor rate							4.25%									4.25%
LIBOR | Rivergate [Member]
Debt Instrument [Line Items]
Debt spread over variable basis percentage																																	2.95%
Line of Credit [Member]
Debt Instrument [Line Items]
Proceeds from debt																													$ 8,000,000
Debt interest rate																													8.00%
Private placement transaction, common stock shares under warrants issued | shares																													750,000				750,000
Loans payable, net																																	$ 3,000,000
Private placement transaction, exercise price of warrants (in usd per share) | $ / shares																													$ 0.0001
Line of Credit [Member] | Monarch Bank Line Of Credit [Member]
Debt Instrument [Line Items]
Loans payable, net																																	$ 2,938,000	3,000,000
Line of Credit [Member] | LIBOR | Monarch Bank Line Of Credit [Member]
Debt Instrument [Line Items]
Debt spread over variable basis percentage																																	3.00%
Senior Convertible Notes [Member]
Debt Instrument [Line Items]
Debt periodic payment		$ 234,199
Debt interest rate		9.00%																									9.00%
Loans payable, net																											$ 3,000,000
Debt prepayment notice period																											30 days
Convertible debt, maximum shares issuable upon conversion | shares																											1,417,079
Conversion of senior convertible debt into Common Stock		$ 1,370,000																																$ 1,640,000
Debt conversion, converted Instrument, shares Issued | shares																																		1,417,079
Promissory Note [Member] | Perimeter Square [Member]
Debt Instrument [Line Items]
Loans payable, net																																																	$ 6,250,000
Promissory Note [Member] | Perimeter Square Construction Loan [Member]
Debt Instrument [Line Items]
Loans payable, net																																						$ 247,000
Promissory Note [Member] | Subsequent Event [Member] | Perimeter Square [Member]
Debt Instrument [Line Items]
Debt interest rate																																					6.50%
Loans payable, net																																					$ 6,250,000
Promissory Note [Member] | Subsequent Event [Member] | Perimeter Square Construction Loan [Member]
Debt Instrument [Line Items]
Debt interest rate																																					6.50%
Loans payable, net																																					$ 247,000
Harbor Point [Member]
Debt Instrument [Line Items]
Loans payable, net																																	$ 460,000	$ 553,000
KeyBank [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Maximum line of credit borrowing capacity																			$ 50,000,000.00									$ 67,200,000																	$ 50,000,000.00	$ 75,000,000.00				$ 75,000,000.0	$ 46,100,000	$ 45,000,000
Interest rate margin above LIBOR, minimum																																																				1.75%
Interest rate margin above LIBOR, maximum																																																				2.50%
Decrease of total commitment on the revolving credit line																			25,000,000
Extension period under revolving credit facility																				60 days													1 year
Debt periodic payment										$ 9,130,000
Borrowings under line of credit																																	$ 52,100,000
Number of collateral properties | property																																	10
Line of credit commitment fee percentage																																	5.02%
Long-term debt maturities in 2019																																	$ 52,100,000
KeyBank [Member] | Line of Credit [Member] | Folly Road [Member]
Debt Instrument [Line Items]
Term of credit facility																								25 years
Loans payable, net																								$ 6,050,000
KeyBank [Member] | Line of Credit [Member] | LIBOR
Debt Instrument [Line Items]
Debt spread over variable basis percentage																												5.00%
KeyBank [Member] | Amended and Restated Credit Agreement [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Maximum line of credit borrowing capacity																	$ 52,500,000.00		50,000,000.00
Debt spread over variable basis percentage																	2.50%
Extension period under revolving credit facility																	1 year
Line of credit current borrowing capacity																																		$ 68,030,000.00						$ 52,500,000.00
Commitment fee percentage on unused capacity																	0.25%
Line of credit, liquidity requirement																																										$ 5,000,000.00	$ 3,500,000.00	$ 5,000,000.00
Line of credit, reduction in borrowing capacity																																							$ 52,500,000			52,500,000
Line of credit, liquidity requirement reduction																																										$ 3,500,000
KeyBank [Member] | Amended and Restated Credit Agreement [Member] | Line of Credit [Member] | Ladson Crossing, Lake Greenwood and South Park [Member]
Debt Instrument [Line Items]
Line of credit paydown																														$ 6,800,000
Over-advance paydown							$ 3,830,000																							$ 3,830,000
KeyBank [Member] | Amended and Restated Credit Agreement [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Accordion feature of line credit																	$ 150,000,000		$ 50,000,000
Revere Loan [Member]
Debt Instrument [Line Items]
Debt periodic payment				$ 575,000		$ 299,000		$ 1,300,000		$ 150,000	$ 2,600,000																						$ 109,658
Debt interest rate					10.00%				10.00%				9.00%																				10.00%	10.00%							8.00%
Loans payable, net									$ 3,500,000				$ 3,500,000																				$ 1,059,000	$ 6,808,000							$ 6,810,000
Debt exit fee			$ 575,000		$ 575,000			$ 75,000					500,000																												$ 360,000
Debt paydown					$ 100,000				$ 500,000
Revere Loan [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Loans payable, net																																$ 505,000
Debt exit fee																																				$ 20,000
Debt paydown	$ 323,000
Loan principal payments																																553,000
Net cash provided by operating activities																																200,000
Jenks Plaza [Member] | Revere Loan [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Cash received from disposal of properties																																323,000
Harbor Point [Member] | Revere Loan [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Cash received from disposal of properties																																$ 30,000
Debt Instrument, Redemption, Period One [Member] | Revere Loan [Member]
Debt Instrument [Line Items]
Debt periodic payment													200,000
Debt Instrument, Redemption, Period Two [Member] | Revere Loan [Member]
Debt Instrument [Line Items]
Debt periodic payment													$ 100,000																				$ 110,000	$ 110,000
JANAF Acquisition [Member]
Debt Instrument [Line Items]
Note assumed in business acquisitions															$ 58,867,000
JANAF Acquisition [Member] | Maturity Date July 2023 [Member]
Debt Instrument [Line Items]
Debt periodic payment															333,159
Note assumed in business acquisitions															$ 53,710,000
Debt interest rate															4.49%
JANAF Acquisition [Member] | Maturity Date January 2026 [Member]
Debt Instrument [Line Items]
Debt interest rate															4.49%
JANAF BJ's [Member] | Maturity Date January 2026 [Member]
Debt Instrument [Line Items]
Debt periodic payment															$ 29,964
Note assumed in business acquisitions															$ 5,160,000
Debt interest rate															4.95%
JANAF Bravo [Member] | Maturity Date January 2026 [Member]
Debt Instrument [Line Items]
Note assumed in business acquisitions															$ 6,500,000
Debt interest rate															4.65%
JANAF Bravo [Member] | Maturity Date January 2021 [Member]
Debt Instrument [Line Items]
Debt periodic payment															$ 36,935