ORGANIZATION - BACs sold and total equity (Details) - USD ($)	3 Months Ended
	Jun. 30, 2020	Mar. 31, 2020
Capital Unit
BACs Sold	83,651,080	83,651,080
Series Twenty [Member]
Capital Unit
Closing Date	Jun. 24, 1994
BACs Sold	3,866,700	3,866,700
Equity Raised	$ 38,667,000
Series Twenty One [Member]
Capital Unit
Closing Date	Dec. 31, 1994
BACs Sold	1,892,700	1,892,700
Equity Raised	$ 18,927,000
Series Twenty Two [Member]
Capital Unit
Closing Date	Dec. 28, 1994
BACs Sold	2,564,400	2,564,400
Equity Raised	$ 25,644,000
Series Twenty Three [Member]
Capital Unit
Closing Date	Jun. 23, 1995
BACs Sold	3,336,727	3,336,727
Equity Raised	$ 33,366,000
Series Twenty Four [Member]
Capital Unit
Closing Date	Sep. 22, 1995
BACs Sold	2,169,878	2,169,878
Equity Raised	$ 21,697,000
Series Twenty Five [Member]
Capital Unit
Closing Date	Dec. 29, 1995
BACs Sold	3,026,109	3,026,109
Equity Raised	$ 30,248,000
Series Twenty Six [Member]
Capital Unit
Closing Date	Jun. 25, 1996
BACs Sold	3,995,900	3,995,900
Equity Raised	$ 39,959,000
Series Twenty Seven [Member]
Capital Unit
Closing Date	Sep. 17, 1996
BACs Sold	2,460,700	2,460,700
Equity Raised	$ 24,607,000
Series Twenty Eight [Member]
Capital Unit
Closing Date	Jan. 29, 1997
BACs Sold	4,000,738	4,000,738
Equity Raised	$ 39,999,000
Series Twenty Nine [Member]
Capital Unit
Closing Date	Jun. 10, 1997
BACs Sold	3,991,800	3,991,800
Equity Raised	$ 39,918,000
Series Thirty [Member]
Capital Unit
Closing Date	Sep. 10, 1997
BACs Sold	2,651,000	2,651,000
Equity Raised	$ 26,490,750
Series Thirty One [Member]
Capital Unit
Closing Date	Jan. 18, 1998
BACs Sold	4,417,857	4,417,857
Equity Raised	$ 44,057,750
Series Thirty Two [Member]
Capital Unit
Closing Date	Jun. 23, 1998
BACs Sold	4,754,198	4,754,198
Equity Raised	$ 47,431,000
Series Thirty Three [Member]
Capital Unit
Closing Date	Sep. 21, 1998
BACs Sold	2,636,533	2,636,533
Equity Raised	$ 26,362,000
Series Thirty Four [Member]
Capital Unit
Closing Date	Feb. 11, 1999
BACs Sold	3,529,319	3,529,319
Equity Raised	$ 35,273,000
Series Thirty Five [Member]
Capital Unit
Closing Date	Jun. 28, 1999
BACs Sold	3,300,463	3,300,463
Equity Raised	$ 33,004,630
Series Thirty Six [Member]
Capital Unit
Closing Date	Sep. 28, 1999
BACs Sold	2,106,838	2,106,838
Equity Raised	$ 21,068,375
Series Thirty Seven [Member]
Capital Unit
Closing Date	Jan. 28, 2000
BACs Sold	2,512,500	2,512,500
Equity Raised	$ 25,125,000
Series Thirty Eight [Member]
Capital Unit
Closing Date	Jul. 31, 2000
BACs Sold	2,543,100	2,543,100
Equity Raised	$ 25,431,000
Series Thirty Nine [Member]
Capital Unit
Closing Date	Jan. 31, 2001
BACs Sold	2,292,151	2,292,151
Equity Raised	$ 22,921,000
Series Forty [Member]
Capital Unit
Closing Date	Jul. 31, 2001
BACs Sold	2,630,256	2,630,256
Equity Raised	$ 26,269,256
Series Forty One [Member]
Capital Unit
Closing Date	Jan. 31, 2002
BACs Sold	2,891,626	2,891,626
Equity Raised	$ 28,916,260
Series Forty Two [Member]
Capital Unit
Closing Date	Jul. 31, 2002
BACs Sold	2,744,262	2,744,262
Equity Raised	$ 27,442,620
Series Forty Three [Member]
Capital Unit
Closing Date	Dec. 31, 2002
BACs Sold	3,637,987	3,637,987
Equity Raised	$ 36,379,870
Series Forty Four [Member]
Capital Unit
Closing Date	Apr. 30, 2003
BACs Sold	2,701,973	2,701,973
Equity Raised	$ 27,019,730
Series Forty Five [Member]
Capital Unit
Closing Date	Sep. 16, 2003
BACs Sold	4,014,367	4,014,367
Equity Raised	$ 40,143,670
Series Forty Six [Member]
Capital Unit
Closing Date	Dec. 19, 2003
BACs Sold	2,980,998	2,980,998
Equity Raised	$ 29,809,980