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INVESTMENT IN UNCONSOLIDATED JOINT VENTURES (Details) |  |  |  |  |  | 1 Months Ended | 12 Months Ended |  |  |  |
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Sep. 30, 2015 USD ($) | Sep. 28, 2015 USD ($) | Oct. 28, 2009 USD ($) item | Oct. 28, 2009 item | Sep. 30, 2004 USD ($) | Aug. 31, 2004 USD ($) | Aug. 31, 2014 USD ($) | Jun. 30, 2013 USD ($) | Oct. 31, 2009 USD ($) | Jan. 31, 2007 USD ($) | Oct. 31, 2004 USD ($) | Dec. 31, 2017 USD ($) item | Dec. 31, 2016 USD ($) item | Dec. 31, 2015 USD ($) item | Dec. 31, 2005 USD ($) item | Feb. 01, 2016 item | Feb. 01, 2015 item | May 31, 2008 item | Mar. 31, 2005 USD ($)
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Investments in joint venture |  |  |  |  |  |  |  |  |  |  |  | $ 7,212,044 | $ 8,336,505 | $ 7,819,162 |  |  |  |  |
Number of units | item |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,033 |  |  |  |  |
Outstanding amount of mortgage |  |  |  |  |  |  |  |  |  |  |  | 233,221,258 | 212,709,080 |  |  |  |  |  |
Number of units sold | item |  |  |  |  |  |  |  |  |  |  |  |  |  | 242 |  |  |  |  |
Number of units retained for long-term investment | item |  |  |  |  |  |  |  |  |  |  |  |  |  | (786) |  |  |  |  |
Unsold units | item |  |  |  |  |  |  |  |  |  |  |  |  |  | 5 |  |  |  |  |
Distribution to the Partnership |  |  |  |  |  |  |  |  |  |  |  | 7,985,835 | $ 6,729,679 | $ 3,785,883 |  |  |  |  |
Mortgages payable |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding amount of mortgage |  |  |  |  |  |  |  |  |  |  |  | $ 233,221,000 |  |  |  |  |  |  |
Investment Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of limited partnerships and limited liability companies in which the entity has invested | item |  |  |  |  |  |  |  |  |  |  |  | 9 |  |  |  |  |  |  |
Number of partnerships investing in commercial property | item |  |  |  |  |  |  |  |  |  |  |  | 3 |  |  |  |  |  |  |
Number of units | item |  |  |  |  |  |  |  |  |  |  |  | 1,033 | 1,033 |  |  |  |  |  |
Number of units sold | item |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 310 | 258 |  |
Number of units retained for long-term investment | item |  |  |  |  |  |  |  |  |  |  |  | (689) | (689) |  |  |  |  |  |
Unsold units | item |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 34 | 38 |  |
Hamilton Company/Management Company |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of employees having ownership interest in the investment properties | item |  |  |  |  |  |  |  |  |  |  |  | 5 |  |  |  |  |  |  |
Dexter Park |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase price of real estate properties |  |  | $ 129,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dexter Park | Mortgage, 5.57%, Due 2019 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage amount |  |  |  |  |  |  |  |  | $ 89,914,000 |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  | 5.57% | 5.57% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Period for which the entity is required to make interest only payments |  |  |  |  |  |  |  |  | 2 years |  |  |  |  |  |  |  |  |  |
Amortization period of debt |  |  |  | 30 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding amount of mortgage |  |  |  |  |  |  |  |  |  |  |  | $ 82,004,000 |  |  |  |  |  |  |
Hamilton Bay Apts |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of units sold | item |  |  |  |  |  |  |  |  |  |  |  | 1 |  |  |  |  |  |  |
Gain on the sale of real estate |  |  |  |  |  |  |  |  |  |  |  | $ 133,000 |  |  |  |  |  |  |
Hamilton Essex Development, LLC and Hamilton Essex 81, LLC | Mortgage, March 2005 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 10,750,000
Repayment of loan | $ 8,040,719 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hamilton Essex 81 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding amount of mortgage |  |  |  |  |  |  |  |  |  |  |  | 10,000,000 |  |  |  |  |  |  |
Hamilton Essex 81 | Mortgage, 2.18% Plus LIBOR, September 2015 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage amount | $ 10,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hamilton Essex 81 | LIBOR | Mortgage, 2.18% Plus LIBOR, September 2015 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Margin over basis of interest rate (as a percent) | 2.18% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis of interest rate | one month LIBOR |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hamilton Essex Development | Mortgage, March 2005 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repayment of loan |  | $ 1,952,286 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hamilton Minuteman |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase price of real estate properties |  |  |  |  | $ 10,100,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Distribution to the Partnership |  |  |  |  |  |  |  |  |  |  | $ 3,775,000 |  |  |  |  |  |  |  |
Hamilton Minuteman | Mortgage, October 2004 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage amount |  |  |  |  |  |  |  |  |  |  | $ 8,025,000 |  |  |  |  |  |  |  |
Hamilton Minuteman | Mortgage, 5.67%, January 2007 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage amount |  |  |  |  |  |  |  |  |  | $ 5,500,000 |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  |  | 5.67% |  |  |  |  |  |  |  |  |
Period for which the entity is required to make interest only payments |  |  |  |  |  |  |  |  |  | 5 months |  |  |  |  |  |  |  |  |
Amortization period of debt |  |  |  |  |  |  |  |  |  | 30 years |  |  |  |  |  |  |  |  |
Term of debt |  |  |  |  |  |  |  |  |  | 10 years |  |  |  |  |  |  |  |  |
Hamilton on Main Apts |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase price of real estate properties |  |  |  |  |  | $ 56,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Number of units sold | item |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 137 |
Distribution to the Partnership |  |  |  |  |  |  | $ 850,000 |  |  |  |  |  |  |  |  |  |  |  |
Hamilton on Main Apts | Mortgage, 5.18%, 2005 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 16,825,000 |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5.18% |  |  |  |
Period for which the entity is required to make interest only payments |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3 years |  |  |  |
Amortization period of debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 30 years |  |  |  |
Term of debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10 years |  |  |  |
Number of buildings | item |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3 |  |  |  |
Repayment of loan |  |  |  |  |  |  | 15,205,000 |  |  |  |  |  |  |  |  |  |  |  |
Term excluding period for which interest only payments to be made |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7 years |  |  |  |
Net proceeds after funding escrow accounts and closing costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 16,700,000 |  |  |  |
Hamilton on Main Apts | Mortgage, 4.34%, August 2014 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage amount |  |  |  |  |  |  | $ 16,900,000 |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  | 4.34% |  |  |  |  |  |  |  |  |  |  |  |
Term of debt |  |  |  |  |  |  | 10 years |  |  |  |  |  |  |  |  |  |  |  |
345 Franklin |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Distribution to the Partnership |  |  |  |  |  |  |  | $ 1,610,000 |  |  |  |  |  |  |  |  |  |  |
345 Franklin | Mortgage, 3.87%, June 2013 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage amount |  |  |  |  |  |  |  | $ 10,000,000 |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  | 3.87% |  |  |  |  |  |  |  |  |  |  |
Period for which the entity is required to make interest only payments |  |  |  |  |  |  |  | 3 years |  |  |  |  |  |  |  |  |  |  |
Amortization period of debt |  |  |  |  |  |  |  | 30 years |  |  |  |  |  |  |  |  |  |  |
Outstanding amount of mortgage |  |  |  |  |  |  |  |  |  |  |  | $ 9,743,000 |  |  |  |  |  |  |
Term of debt |  |  |  |  |  |  |  | 15 years |  |  |  |  |  |  |  |  |  |  |
345 Franklin | Mortgage, Paid off June 2013 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repayment of loan |  |  |  |  |  |  |  | $ 6,776,000 |  |  |  |  |  |  |  |  |  |  |
Residential buildings |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of units | item |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,030 |  |  |  |  |
Residential buildings | Investment Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of units | item |  |  |  |  |  |  |  |  |  |  |  | 1,030 | 1,030 |  |  |  |  |  |
Residential buildings | Dexter Park |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of units | item |  |  | 409 | 409 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commercial |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of units | item |  |  |  |  |  |  |  |  |  |  |  |  |  | 3 |  |  |  |  |
Commercial | Investment Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of units | item |  |  |  |  |  |  |  |  |  |  |  | 3 | 3 |  |  |  |  |  |
Minimum | Mortgages payable |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 3.24% |  |  |  |  |  |  |
Minimum | Investment Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 40.00% |  |  |  |  |  |  |
Minimum | Harold Brown | Investment Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest of related party (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 43.20% |  |  |  |  |  |  |
Maximum | Mortgages payable |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 5.97% |  |  |  |  |  |  |
Maximum | Investment Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  |  |  |  |
Maximum | Harold Brown | Investment Properties |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
INVESTMENT IN UNCONSOLIDATED JOINT VENTURES |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest of related party (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 56.00% |  |  |  |  |  |  |

X
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- Definition Number of employees, excluding President, having ownership interest in the investment properties. + References No definition available. + Details
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