Loans Payable - Summary of Loans Payable (Detail) - USD ($) | Apr. 28, 2016 | Apr. 08, 2016 | Sep. 30, 2016 | Sep. 30, 2015 | Aug. 15, 2016 | Jul. 29, 2016 | Jul. 11, 2016 | Apr. 12, 2016 | Dec. 31, 2015 | May 29, 2015 |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 231,767,262 | | | $ 4,100,000 | | | $ 184,629,082 | |
Secured debt, gross of unamortized debt issuance cost | | | 238,551,135 | | | | | | 189,340,456 | |
Deferred Finance Costs, Net | | | $ (6,783,873) | | | | | | $ (4,711,374) | |
Common Stock, Par or Stated Value Per Share | | | $ 0.01 | | | | | | $ 0.01 | |
Conversion of senior convertible debt into common stock | | | $ 1,600,000 | $ 0 | | | | | | |
KeyBank [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | | | | | $ 4,600,000 | | | |
Mortgage Loans Payable, Interest Rate | | | | | | | 4.70% | | | |
Line of Credit [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgage Loans Payable, Interest Rate | | 8.00% | | | | | | | | |
Proceeds from issuance of secured debt | | $ 8,000,000 | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | | 6,000,000 | 6,000,000 | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights | | $ 0.0001 | | | | | | | | |
Line of Credit [Member] | Vantage South Bank [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 3,000,000 | | | | | | $ 0 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.25% | | | | | | | |
Line of Credit [Member] | Monarch Bank Line Of Credit [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2017-09 | | | | | | | |
Line of Credit [Member] | KeyBank [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Interest rate margin above LIBOR, minimum | | | | | | | | | | 1.75% |
Interest rate margin above LIBOR, maximum | | | | | | | | | | 2.50% |
Mortgages and other indebtedness | | | $ 46,127,250 | | | | $ 3,900,000 | | 6,873,750 | |
Proceeds from Issuance of Convertible Preferred Stock | | | $ 46,100,000 | | $ 46,100,000 | | | | | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 3.01% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2018-05 | | | | | | | |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | | | 0.30% | | | | | | | |
Line of Credit Facility, Maximum Borrowing Capacity | | | | | | | | $ 67,200,000 | | $ 45,000,000 |
Line of Credit Facility, Commitment Fee Percentage | | | 3.01% | | | | | | | |
Line of Credit [Member] | Revere Loan [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Proceeds from issuance of secured debt | | | $ 7,450,000 | | | | | | | |
Senior Convertible Notes [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | $ 3,000,000 | | $ 1,400,000 | | | | | | 3,000,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | 9.00% | | 9.00% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2018-12 | | | | | | | |
Prepayment notice period | 30 days | | | | | | | | | |
Number of shares issuable upon conversion (in shares) | 1,417,079 | | | | | | | | | |
Conversion of senior convertible debt into common stock | | | $ 1,600,000 | | | | | | | |
Debt Conversion, Converted Instrument, Shares Issued | | | 1,397,010 | | | | | | | |
Senior Non-Convertible Notes [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 0 | | | | | | 2,160,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 9.00% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2016-01 | | | | | | | |
Debt Instrument, Face Amount | | | $ 2,160,000 | | | | | | | |
Shoppes at Eagle Harbor [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | 3,528,895 | | | | | | 3,634,085 | |
Mortgage Loans Payable, Monthly Payment | | | $ 25,100 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.34% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2018-03 | | | | | | | |
Monarch Bank Building [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 1,334,241 | | | | | | 1,376,452 | |
Mortgage Loans Payable, Monthly Payment | | | $ 9,473 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.15% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2017-12 | | | | | | | |
Perimeter Square [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 4,500,000 | | | $ 4,500,000 | | | 4,166,406 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.06% | | | 4.06% | | | | |
Mortgage Loans Payable, Maturity Period | | | 2026-08 | | | | | | | |
Riversedge North [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 926,444 | | | | | | 962,281 | |
Mortgage Loans Payable, Monthly Payment | | | $ 8,802 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 6.00% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2019-01 | | | | | | | |
Walnut Hill Plaza [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 3,464,362 | | | | | | 3,535,606 | |
Mortgage Loans Payable, Monthly Payment | | | $ 24,273 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 5.50% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2017-07 | | | | | | | |
Twin City Commons [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 3,184,056 | | | | | | 3,225,473 | |
Mortgage Loans Payable, Monthly Payment | | | $ 17,827 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.86% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2023-01 | | | | | | | |
Shoppes at TJ Maxx [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 5,951,648 | | | | | | 6,081,272 | |
Mortgage Loans Payable, Monthly Payment | | | $ 33,880 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 3.88% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2020-05 | | | | | | | |
Forrest Gallery [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 8,834,660 | | | | | | 8,926,712 | |
Mortgage Loans Payable, Monthly Payment | | | $ 50,973 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 5.40% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2023-09 | | | | | | | |
Tampa Festival [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 8,534,790 | | | | | | 8,627,294 | |
Mortgage Loans Payable, Monthly Payment | | | $ 50,797 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 5.56% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2023-09 | | | | | | | |
Winslow Plaza [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 4,620,000 | | | | | | 4,620,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.82% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-12 | | | | | | | |
Cypress Shopping Center [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 6,609,876 | | | | | | 6,625,000 | |
Mortgage Loans Payable, Monthly Payment | | | $ 34,360 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.70% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2024-07 | | | | | | | |
Harrodsburg Marketplace [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 3,632,616 | | | | | | 3,677,501 | |
Mortgage Loans Payable, Monthly Payment | | | $ 19,112 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.55% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2024-09 | | | | | | | |
Port Crossing Shopping Center [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 6,396,584 | | | | | | 6,471,636 | |
Mortgage Loans Payable, Monthly Payment | | | $ 34,788 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.84% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2024-08 | | | | | | | |
LaGrange Marketplace [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 2,381,726 | | | | | | 2,418,212 | |
Mortgage Loans Payable, Monthly Payment | | | $ 15,065 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 5.50% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2020-03 | | | | | | | |
Freeway Junction [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 8,150,000 | | | | | | 8,150,000 | |
Mortgage Loans Payable, Monthly Payment | | | $ 31,265 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.60% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2024-09 | | | | | | | |
DF I-Edenton [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Debt Instrument, Periodic Payment, Principal | | | $ 250,000 | | | | | | | |
Mortgages and other indebtedness | | | 0 | | | | | | 650,000 | |
Mortgage Loans Payable, Monthly Payment | | | $ 250,000 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 3.75% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2016-09 | | | | | | | |
DF I-Moyock [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 337,169 | | | | | | 418,538 | |
Mortgage Loans Payable, Monthly Payment | | | $ 10,665 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 5.00% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2019-07 | | | | | | | |
Graystone Crossing [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 4,000,000 | | | | | | 4,000,000 | |
Mortgage Loans Payable, Monthly Payment | | | 15,672 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.55% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2024-10 | | | | | | | |
Bryan Station [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 4,625,000 | | | | | | 4,625,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.52% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2024-11 | | | | | | | |
Crockett Square [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 6,337,500 | | | | | | 6,337,500 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.47% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2024-12 | | | | | | | |
Harbor Point [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 664,864 | | | | | | 732,685 | |
Mortgage Loans Payable, Monthly Payment | | | $ 11,024 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 5.85% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2016-12 | | | | | | | |
Pierpont Centre [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 8,450,000 | | | | | | 8,450,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.15% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-02 | | | | | | | |
Alex City Marketplace [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 5,750,000 | | | | | | 5,750,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 3.95% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-04 | | | | | | | |
Butler Square [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 5,640,000 | | | | | | 5,640,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 3.90% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-05 | | | | | | | |
Brook Run Shopping Center [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 10,950,000 | | | | | | 10,950,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.08% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-06 | | | | | | | |
Beaver Village I and II [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 9,400,000 | | | | | | 9,400,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.73% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-07 | | | | | | | |
Columbia Fire Station [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 477,788 | | | | | | 450,053 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 8.00% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-07 | | | | | | | |
Sunshine Plaza [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 5,900,000 | | | | | | 5,900,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.57% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-08 | | | | | | | |
Barnett Portfolio [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 8,770,000 | | | | | | 8,770,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.30% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-09 | | | | | | | |
Grove Park Shopping Center [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 3,800,000 | | | | | | 3,800,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.52% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-10 | | | | | | | |
Parkway Plaza Shopping Center [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 3,500,000 | | | | | | 3,500,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.57% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-10 | | | | | | | |
Conyers Crossing [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 5,960,000 | | | | | | 5,960,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.67% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-10 | | | | | | | |
Ft. Howard Square [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 7,100,000 | | | | | | 7,100,000 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.57% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2025-10 | | | | | | | |
Revere Loan [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 7,450,000 | | | | | | 0 | |
Mortgage Loans Payable, Monthly Payment | | | Interest only | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 8.00% | | | | | | | |
South Carolina Food Lions Note [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 12,266,906 | | | | | | 12,375,000 | |
Mortgage Loans Payable, Monthly Payment | | | $ 68,320 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 5.25% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2024-01 | | | | | | | |
Chesapeake Square [Member] | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | |
Mortgages and other indebtedness | | | $ 4,594,760 | | | | | | $ 0 | |
Mortgage Loans Payable, Monthly Payment | | | $ 23,857 | | | | | | | |
Mortgage Loans Payable, Interest Rate | | | 4.70% | | | | | | | |
Mortgage Loans Payable, Maturity Period | | | 2026-08 | | | | | | | |