Quarterly report pursuant to Section 13 or 15(d)

Loans Payable - Additional Information (Details)

v3.19.1
Loans Payable - Additional Information (Details)
3 Months Ended
Mar. 29, 2019
USD ($)
Mar. 19, 2019
USD ($)
Feb. 07, 2019
USD ($)
a
Jan. 29, 2019
USD ($)
Jan. 11, 2019
USD ($)
Dec. 31, 2018
USD ($)
property
director
quarter
Oct. 15, 2018
USD ($)
Dec. 21, 2017
Mar. 31, 2019
USD ($)
parcel
property
Jan. 15, 2019
USD ($)
Debt Instrument [Line Items]                    
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months                 $ 90,830,000  
Debt instrument, interest rate. stated percentage                 5.00%  
Loans payable, net           $ 360,117,000     $ 348,651,000  
Number of undeveloped parcels | parcel                 6  
Perimeter Square Loan and Perimeter Square Construction Loan [Member]                    
Debt Instrument [Line Items]                    
Loans payable, net                 $ 6,500,000  
First National Bank Line of Credit                    
Debt Instrument [Line Items]                    
Line of Credit Facility, Maximum Borrowing Capacity         $ 1,510,000          
Debt instrument, periodic payment                 24,656  
Loans payable, net           2,938,000     1,379,000  
Deutsche Bank                    
Debt Instrument [Line Items]                    
Debt instrument, periodic payment                 $ 33,340  
Debt instrument, interest rate. stated percentage                 5.71%  
Loans payable, net           5,713,000     $ 5,695,000  
Revere Loan                    
Debt Instrument [Line Items]                    
Debt instrument, periodic payment $ 406,000   $ 30,000   $ 323,000       300,000  
Twin City Commons                    
Debt Instrument [Line Items]                    
Debt instrument, periodic payment                 $ 48,747  
Debt instrument, interest rate. stated percentage                 5.65%  
Loans payable, net           6,907,000     $ 6,859,000  
Lumber River                    
Debt Instrument [Line Items]                    
Debt instrument, periodic payment                 10,723  
Loans payable, net           1,448,000     $ 1,438,000  
Lumber River | LIBOR                    
Debt Instrument [Line Items]                    
Debt instrument, basis spread on variable rate                 3.50%  
Benefit Street                    
Debt Instrument [Line Items]                    
Debt instrument, periodic payment                 $ 53,185  
Debt instrument, interest rate. stated percentage                 5.71%  
Loans payable, net           7,567,000     $ 7,515,000  
Perimeter Square                    
Debt Instrument [Line Items]                    
Debt instrument, interest rate. stated percentage                 6.50% 6.50%
Loans payable, net           6,250,000     $ 6,250,000 $ 6,250,000
Perimeter Square Construction Loan                    
Debt Instrument [Line Items]                    
Debt instrument, interest rate. stated percentage                 6.50%  
Loans payable, net           247,000     $ 247,000 $ 247,000
Revere Loan                    
Debt Instrument [Line Items]                    
Debt instrument, periodic payment       $ 20,000         $ 109,658  
Debt instrument, interest rate. stated percentage                 10.00%  
Loans payable, net           $ 1,059,000     $ 0  
Line of Credit | First National Bank Line of Credit | LIBOR                    
Debt Instrument [Line Items]                    
Debt instrument, basis spread on variable rate                 3.50%  
Line of Credit | KeyBank                    
Debt Instrument [Line Items]                    
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months                 $ 51,250,000  
Line of credit facility, extension period                 1 year  
Debt instrument, periodic payment   $ 850,000                
Long-term Line of Credit                 $ 51,250,000  
Number of collateral properties | property           10     10  
Line of Credit Facility, Commitment Fee Percentage                 5.00%  
Line of Credit | KeyBank | Amended and Restated Credit Agreement                    
Debt Instrument [Line Items]                    
Line of credit facility, extension period               1 year 1 year  
Debt instrument, basis spread on variable rate                 2.50%  
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage               0.25%    
Line of Credit | KeyBank | Ladson Crossing, Lake Greenwood and South Park [Member] | Amended and Restated Credit Agreement                    
Debt Instrument [Line Items]                    
Repayments of overadvance           $ 3,830,000 $ 2,980,000      
Harbor Point | Disposal Group, Disposed of by Sale, Not Discontinued Operations                    
Debt Instrument [Line Items]                    
Area of real estate property leased | a     1.28              
Series D Preferred Stock                    
Debt Instrument [Line Items]                    
Preferred Stock, Minimum Consecutive Quarterly Periods for Dividends in Arrears | quarter           6        
Number of Additional Directors | director           2        
Preferred Stock, Percentage of Holders of Shares Outstanding           20.00%