RENTAL PROPERTIES - Real Estate (Details) - USD ($)	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	$ 531,030,558
Initial Cost to Partnerships
Land	136,826,811
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	99,253,764
Gross Amount at Which Carried at Close of Period
Land	136,983,339
Building Improvements	519,019,050
Totals	656,002,391	$ 461,409,491	$ 440,496,897	$ 400,703,910
Accumulated Depreciation	194,614,338	$ 182,892,842	$ 170,691,951	$ 159,627,479
Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 419,765,286
Buildings and improvements | Minimum
Gross Amount at Which Carried at Close of Period
Estimated useful lives	10 years
Buildings and improvements | Maximum
Gross Amount at Which Carried at Close of Period
Estimated useful lives	40 years
Other Categories of Assets | Minimum
Gross Amount at Which Carried at Close of Period
Estimated useful lives	5 years
Other Categories of Assets | Maximum
Gross Amount at Which Carried at Close of Period
Estimated useful lives	15 years
Boylston Downtown L.P. Residential Apartments Boston, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	$ 32,160,432
Initial Cost to Partnerships
Land	2,112,000
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	11,699,220
Gross Amount at Which Carried at Close of Period
Land	2,268,528
Building Improvements	20,292,329
Totals	22,560,857
Accumulated Depreciation	$ 16,107,160
Estimated useful lives	3 years
Boylston Downtown L.P. Residential Apartments Boston, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 8,593,109
Brighton 26 & Concord 90 NERA LLC Belmont,Massachusetts
Initial Cost to Partnerships
Land	1,119,253
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	1,489,273
Gross Amount at Which Carried at Close of Period
Land	1,119,253
Building Improvements	1,489,273
Totals	$ 2,608,526
Estimated useful lives	3 years
Brookside Associates LLC Residential Apartments Woburn, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	$ 6,175,000
Initial Cost to Partnerships
Land	684,000
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	1,128,124
Gross Amount at Which Carried at Close of Period
Land	684,000
Building Improvements	4,244,124
Totals	4,928,124
Accumulated Depreciation	$ 3,230,369
Estimated useful lives	3 years
Brookside Associates LLC Residential Apartments Woburn, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 3,116,000
Clovelly Apartments L.P. Residential Apartments Nashua, New Hampshire
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	10,704,080
Initial Cost to Partnerships
Land	177,610
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	2,572,805
Gross Amount at Which Carried at Close of Period
Land	177,610
Building Improvements	4,051,164
Totals	4,228,774
Accumulated Depreciation	$ 2,676,852
Estimated useful lives	3 years
Clovelly Apartments L.P. Residential Apartments Nashua, New Hampshire | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 1,478,359
Commonwealth 1137 L.P. Residential Apartments Boston, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	9,608,410
Initial Cost to Partnerships
Land	342,000
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	2,890,790
Gross Amount at Which Carried at Close of Period
Land	342,000
Building Improvements	4,258,459
Totals	4,600,459
Accumulated Depreciation	$ 2,052,793
Estimated useful lives	3 years
Commonwealth 1137 L.P. Residential Apartments Boston, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 1,367,669
Commonwealth 1144 L.P. Residential Apartments Boston, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	59,987,234
Initial Cost to Partnerships
Land	1,410,000
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	7,675,415
Gross Amount at Which Carried at Close of Period
Land	1,410,000
Building Improvements	13,340,231
Totals	14,750,231
Accumulated Depreciation	$ 8,405,818
Estimated useful lives	3 years
Commonwealth 1144 L.P. Residential Apartments Boston, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 5,664,816
Executive Apartments L.P. Residential Apartments Framingham, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	7,616,967
Initial Cost to Partnerships
Land	91,400
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	4,063,277
Gross Amount at Which Carried at Close of Period
Land	91,400
Building Improvements	4,803,637
Totals	4,895,037
Accumulated Depreciation	$ 2,002,586
Estimated useful lives	3 years
Executive Apartments L.P. Residential Apartments Framingham, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 740,360
Hamilton Battle Green LLC Residential Apartments Lexington, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	3,485,948
Initial Cost to Partnerships
Land	1,341,737
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	587,958
Gross Amount at Which Carried at Close of Period
Land	1,341,737
Building Improvements	9,045,455
Totals	10,387,192
Accumulated Depreciation	$ 5,085,821
Estimated useful lives	3 years
Hamilton Battle Green LLC Residential Apartments Lexington, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 8,457,497
Hamilton Cypress LLC Commercial-1031 Exchange Brookline, Massachusetts
Initial Cost to Partnerships
Land	2,362,795
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	405,972
Gross Amount at Which Carried at Close of Period
Land	2,362,795
Building Improvements	5,019,758
Totals	7,382,553
Accumulated Depreciation	$ 2,244,555
Estimated useful lives	3 years
Hamilton Cypress LLC Commercial-1031 Exchange Brookline, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 4,613,786
Hamilton Green Apartments, LLC Residential Apartments Andover, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	30,442,405
Initial Cost to Partnerships
Land	15,413,457
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	(7,813,386)
Gross Amount at Which Carried at Close of Period
Land	15,413,457
Building Improvements	37,621,931
Totals	53,035,387
Accumulated Depreciation	$ 20,053,644
Estimated useful lives	3 years
Hamilton Green Apartments, LLC Residential Apartments Andover, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 45,435,317
Hamilton Highlands, LLC Residential Apartments Needham, Massachsetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	20,511,229
Initial Cost to Partnerships
Land	7,973,547
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	(3,300,544)
Gross Amount at Which Carried at Close of Period
Land	7,973,547
Building Improvements	22,803,518
Totals	30,777,066
Accumulated Depreciation	$ 7,145,785
Estimated useful lives	3 years
Hamilton Highlands, LLC Residential Apartments Needham, Massachsetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 26,104,062
Hamilton Linewt LLC Commercial 1031 Exchange Newton, Massachusetts
Initial Cost to Partnerships
Land	984,522
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	218,097
Gross Amount at Which Carried at Close of Period
Land	984,522
Building Improvements	2,769,744
Totals	3,754,266
Accumulated Depreciation	$ 1,274,466
Estimated useful lives	3 years
Hamilton Linewt LLC Commercial 1031 Exchange Newton, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 2,551,647
Hamilton Oaks Associates LLC Residential Apartments Brockton, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	28,712,824
Initial Cost to Partnerships
Land	2,245,236
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	7,991,814
Gross Amount at Which Carried at Close of Period
Land	2,245,236
Building Improvements	20,246,578
Totals	22,491,814
Accumulated Depreciation	$ 15,856,402
Estimated useful lives	3 years
Hamilton Oaks Associates LLC Residential Apartments Brockton, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 12,254,764
Highland Street Apartments, L.P. Residential Apartments Lowell, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	4,084,284
Initial Cost to Partnerships
Land	156,000
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	460,284
Gross Amount at Which Carried at Close of Period
Land	156,000
Building Improvements	1,094,369
Totals	1,250,369
Accumulated Depreciation	$ 906,087
Estimated useful lives	3 years
Highland Street Apartments, L.P. Residential Apartments Lowell, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 634,085
Hill Estates NERA, LLC , Belmont,Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	67,656,000
Initial Cost to Partnerships
Land	41,136,002
Gross Amount at Which Carried at Close of Period
Land	41,136,002
Building Improvements	128,923,609
Totals	170,059,611
Accumulated Depreciation	$ 4,658,889
Estimated useful lives	3 years
Hill Estates NERA, LLC , Belmont,Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 128,923,609
Linhart L.P. Residential/Commercial Newton, Massachusetts
Initial Cost to Partnerships
Land	385,000
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	1,572,005
Gross Amount at Which Carried at Close of Period
Land	385,000
Building Improvements	3,112,005
Totals	3,497,005
Accumulated Depreciation	$ 2,568,076
Estimated useful lives	3 years
Linhart L.P. Residential/Commercial Newton, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 1,540,000
Mill Street Gardens, LLC Residential Apartments Woburn, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	30,463,392
Initial Cost to Partnerships
Land	12,689,705
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	(1,738,867)
Gross Amount at Which Carried at Close of Period
Land	12,689,705
Building Improvements	38,938,818
Totals	51,628,522
Accumulated Depreciation	$ 11,564,674
Estimated useful lives	3 years
Mill Street Gardens, LLC Residential Apartments Woburn, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 40,677,685
Mill Street Heights,Woburn, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	17,500,000
Initial Cost to Partnerships
Land	1,376,031
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	32,356,178
Gross Amount at Which Carried at Close of Period
Land	1,376,031
Building Improvements	33,480,147
Totals	$ 34,856,179
Estimated useful lives	3 years
Mill Street Heights,Woburn, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 1,123,969
NERA Dean St. Associates LLC Residential Apartments Norwood, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	9,732,984
Initial Cost to Partnerships
Land	1,516,015
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	2,063,495
Gross Amount at Which Carried at Close of Period
Land	1,516,015
Building Improvements	7,760,960
Totals	9,276,975
Accumulated Depreciation	$ 6,136,579
Estimated useful lives	3 years
NERA Dean St. Associates LLC Residential Apartments Norwood, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 5,697,465
North Beacon 140 L.P. Residential Apartments Boston, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	16,628,581
Initial Cost to Partnerships
Land	1,200,620
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	2,599,330
Gross Amount at Which Carried at Close of Period
Land	1,200,620
Building Improvements	6,096,723
Totals	7,297,343
Accumulated Depreciation	$ 5,569,122
Estimated useful lives	3 years
North Beacon 140 L.P. Residential Apartments Boston, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 3,497,393
Olde English Apartments L.P. Residential Apartments Lowell, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	10,254,456
Initial Cost to Partnerships
Land	77,454
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	1,307,232
Gross Amount at Which Carried at Close of Period
Land	77,454
Building Improvements	2,154,282
Totals	2,231,737
Accumulated Depreciation	$ 1,630,457
Estimated useful lives	3 years
Olde English Apartments L.P. Residential Apartments Lowell, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 847,050
Redwood Hills L.P. Residential Apartments Worcester, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	19,558,674
Initial Cost to Partnerships
Land	1,278,412
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	7,055,666
Gross Amount at Which Carried at Close of Period
Land	1,278,412
Building Improvements	11,787,858
Totals	13,066,270
Accumulated Depreciation	$ 8,989,442
Estimated useful lives	3 years
Redwood Hills L.P. Residential Apartments Worcester, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 4,732,192
Residences at Captain Parkers LLC Residential Apartments Lexington, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	20,750,000
Initial Cost to Partnerships
Land	7,755,055
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	797,815
Gross Amount at Which Carried at Close of Period
Land	7,755,055
Building Improvements	24,244,690
Totals	31,999,745
Accumulated Depreciation	$ 9,588,584
Estimated useful lives	3 years
Residences at Captain Parkers LLC Residential Apartments Lexington, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 23,446,875
River Drive L.P. Residential Apartments Danvers, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	7,138,950
Initial Cost to Partnerships
Land	109,697
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	2,651,262
Gross Amount at Which Carried at Close of Period
Land	109,697
Building Improvements	3,201,867
Totals	3,311,564
Accumulated Depreciation	$ 1,457,941
Estimated useful lives	3 years
River Drive L.P. Residential Apartments Danvers, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 550,605
Riverside Apartments Condominium Units Watertown Massachustts
Initial Cost to Partnerships
Land	23,346
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	168,295
Gross Amount at Which Carried at Close of Period
Land	23,346
Building Improvements	359,102
Totals	382,448
Accumulated Depreciation	$ 330,965
Estimated useful lives	3 years
Riverside Apartments Condominium Units Watertown Massachustts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 190,807
School St Assoc LLC Residential Apartments Framingham, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	26,917,222
Initial Cost to Partnerships
Land	4,686,728
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	1,107,449
Gross Amount at Which Carried at Close of Period
Land	4,686,728
Building Improvements	19,854,360
Totals	24,541,088
Accumulated Depreciation	$ 15,042,100
Estimated useful lives	3 years
School St Assoc LLC Residential Apartments Framingham, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 18,746,911
WRF Associates LLC Strip Mall Framingham, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	6,499,565
Initial Cost to Partnerships
Land	3,280,000
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	1,172,297
Gross Amount at Which Carried at Close of Period
Land	3,280,000
Building Improvements	6,092,297
Totals	9,372,297
Accumulated Depreciation	$ 4,550,683
Estimated useful lives	3 years
WRF Associates LLC Strip Mall Framingham, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 4,920,000
WCB Associates LLC Residential Apartments Brockton, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	17,151,791
Initial Cost to Partnerships
Land	1,719,517
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	4,008,498
Gross Amount at Which Carried at Close of Period
Land	1,719,517
Building Improvements	11,189,482
Totals	12,908,998
Accumulated Depreciation	$ 9,418,754
Estimated useful lives	3 years
WCB Associates LLC Residential Apartments Brockton, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 7,180,984
Westgate Apartments Burlington LLC Residential Apartments Burlington, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	5,446,485
Initial Cost to Partnerships
Land	191,275
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	366,132
Gross Amount at Which Carried at Close of Period
Land	191,275
Building Improvements	4,698,509
Totals	4,889,784
Accumulated Depreciation	$ 3,763,851
Estimated useful lives	3 years
Westgate Apartments Burlington LLC Residential Apartments Burlington, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 4,332,377
Westgate Apartments LLC Residential Apartments Woburn, Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	40,893,829
Initial Cost to Partnerships
Land	521,495
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	7,726,426
Gross Amount at Which Carried at Close of Period
Land	521,495
Building Improvements	10,090,867
Totals	10,612,362
Accumulated Depreciation	$ 7,077,944
Estimated useful lives	3 years
Westgate Apartments LLC Residential Apartments Woburn, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 2,364,441
Woodland Park Apartments LLC Residential Apartments Newton Massachusetts
Real estate and accumulated depreciation
Encumbrances (First Mortgages)	20,949,816
Initial Cost to Partnerships
Land	11,754,450
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	(3,005,144)
Gross Amount at Which Carried at Close of Period
Land	11,754,450
Building Improvements	30,229,734
Totals	41,984,185
Accumulated Depreciation	$ 10,869,761
Estimated useful lives	3 years
Woodland Park Apartments LLC Residential Apartments Newton Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 33,234,878
653 Worcester Rd, Framingham, Massachusetts
Initial Cost to Partnerships
Land	3,415,051
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	1,218,488
Gross Amount at Which Carried at Close of Period
Land	3,415,051
Building Improvements	5,715,337
Totals	9,130,389
Accumulated Depreciation	$ 1,340,878
Estimated useful lives	3 years
653 Worcester Rd, Framingham, Massachusetts | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 4,496,849
Shawmut Place LLC Boston, Massachuseyys
Initial Cost to Partnerships
Land	7,297,401
Cost Capitalized Subsequent to Acquisition
Improvements, Net of retirements	7,758,108
Gross Amount at Which Carried at Close of Period
Land	7,297,401
Building Improvements	20,007,833
Totals	27,305,234
Accumulated Depreciation	$ 3,013,300
Estimated useful lives	3 years
Shawmut Place LLC Boston, Massachuseyys | Buildings and improvements
Initial Cost to Partnerships
Building Improvements	$ 12,249,725