INVESTMENTS IN OPERATING PARTNERSHIPS (Details 3) - USD ($)		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Revenues
Rental		$ 2,700,506	$ 3,263,242
Interest and other		51,169	62,042
Operating Partnerships Revenues		2,751,675	3,325,284
Expenses
Interest		313,528	408,660
Depreciation and amortization		666,206	845,960
Operating expenses		2,042,583	2,514,133
Operating Partnerships Total Expenses		3,022,317	3,768,753
NET LOSS		(270,642)	(443,469)
Net loss allocated to Boston Capital Tax Credit Fund III L.P.	[1]	(267,934)	(439,032)
Net loss allocated to other Partners		(2,708)	(4,437)
Series Fifteen [Member]
Revenues
Rental		592,173	725,157
Interest and other		13,524	12,202
Operating Partnerships Revenues		605,697	737,359
Expenses
Interest		76,495	98,002
Depreciation and amortization		137,899	187,833
Operating expenses		412,557	560,078
Operating Partnerships Total Expenses		626,951	845,913
NET LOSS		(21,254)	(108,554)
Net loss allocated to Boston Capital Tax Credit Fund III L.P.	[2]	(21,041)	(107,468)
Net loss allocated to other Partners		(213)	(1,086)
Series Sixteen [Member]
Revenues
Rental		850,747	1,126,696
Interest and other		12,292	16,743
Operating Partnerships Revenues		863,039	1,143,439
Expenses
Interest		101,234	144,524
Depreciation and amortization		190,845	290,726
Operating expenses		597,955	814,159
Operating Partnerships Total Expenses		890,034	1,249,409
NET LOSS		(26,995)	(105,970)
Net loss allocated to Boston Capital Tax Credit Fund III L.P.	[3]	(26,725)	(104,910)
Net loss allocated to other Partners		(270)	(1,060)
Series Seventeen [Member]
Revenues
Rental		534,473	700,583
Interest and other		9,481	12,712
Operating Partnerships Revenues		543,954	713,295
Expenses
Interest		55,779	88,135
Depreciation and amortization		164,820	195,800
Operating expenses		414,539	533,854
Operating Partnerships Total Expenses		635,138	817,789
NET LOSS		(91,184)	(104,494)
Net loss allocated to Boston Capital Tax Credit Fund III L.P.	[4]	(90,271)	(103,448)
Net loss allocated to other Partners		(913)	(1,046)
Series Eighteen [Member]
Revenues
Rental		536,554	523,605
Interest and other		10,682	16,560
Operating Partnerships Revenues		547,236	540,165
Expenses
Interest		55,544	54,430
Depreciation and amortization		131,833	131,150
Operating expenses		460,742	442,777
Operating Partnerships Total Expenses		648,119	628,357
NET LOSS		(100,883)	(88,192)
Net loss allocated to Boston Capital Tax Credit Fund III L.P.	[5]	(99,874)	(87,310)
Net loss allocated to other Partners		(1,009)	(882)
Series Nineteen [Member]
Revenues
Rental		186,559	187,201
Interest and other		5,190	3,825
Operating Partnerships Revenues		191,749	191,026
Expenses
Interest		24,476	23,569
Depreciation and amortization		40,809	40,451
Operating expenses		156,790	163,265
Operating Partnerships Total Expenses		222,075	227,285
NET LOSS		(30,326)	(36,259)
Net loss allocated to Boston Capital Tax Credit Fund III L.P.	[6]	(30,023)	(35,896)
Net loss allocated to other Partners		$ (303)	$ (363)

[1] Amounts include $267,934 and $439,032 for 2016 and 2015, respectively, of loss not recognized under the equity method of accounting.

[2] Amounts include $21,041 and $107,468 for 2016 and 2015, respectively, of loss not recognized under the equity method of accounting.

[3] Amounts include $26,725 and $104,910 for 2016 and 2015, respectively, of loss not recognized under the equity method of accounting.

[4] Amounts include $90,271 and $103,448 for 2016 and 2015, respectively, of loss not recognized under the equity method of accounting.

[5] Amounts include $99,874 and $87,310 for 2016 and 2015, respectively, of loss not recognized under the equity method of accounting.

[6] Amounts include $30,023 and $35,896 for 2016 and 2015, respectively, of loss not recognized under the equity method of accounting.