CONDENSED BALANCE SHEETS (USD $)	Dec. 31, 2014	Mar. 31, 2014
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	$ 4,547,778us-gaap_RealEstateInvestmentPropertyNet	$ 5,328,701us-gaap_RealEstateInvestmentPropertyNet
OTHER ASSETS
Cash and cash equivalents	19,383,611	12,797,054
Notes receivable	22,790us-gaap_NotesReceivableNet	22,790us-gaap_NotesReceivableNet
Acquisition costs, net	150,282bctciv_DeferredAcquisitionCostsNet	200,376bctciv_DeferredAcquisitionCostsNet
Other assets	281,681us-gaap_OtherAssets	180,417us-gaap_OtherAssets
ASSETS	24,386,142us-gaap_Assets	18,529,338us-gaap_Assets
LIABILITIES
Accounts payable and accrued expenses	222,863	160,120
Accounts payable affiliates (Note C)	51,153,049	50,042,235
Capital contributions payable	619,106bctciv_CapitalContributionsPayable	664,260bctciv_CapitalContributionsPayable
LIABILITIES	51,995,018us-gaap_Liabilities	50,866,615us-gaap_Liabilities
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(20,166,565)us-gaap_LimitedPartnersCapitalAccount	(24,847,683)us-gaap_LimitedPartnersCapitalAccount
General Partner	(7,442,311)us-gaap_GeneralPartnersCapitalAccount	(7,489,594)us-gaap_GeneralPartnersCapitalAccount
PARTNERS' CAPITAL (DEFICIT)	(27,608,876)us-gaap_PartnersCapital	(32,337,277)us-gaap_PartnersCapital
Liabilities and Stockholders' Equity	24,386,142	18,529,338
Series Twenty [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	324,710	204,785
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	324,710	204,785
LIABILITIES
Accounts payable and accrued expenses	9,000	0
Accounts payable affiliates (Note C)	1,496,449	1,488,111
Capital contributions payable	0	0
LIABILITIES	1,505,449	1,488,111
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(860,680)	(962,241)
General Partner	(320,059)	(321,085)
PARTNERS' CAPITAL (DEFICIT)	(1,180,739)	(1,283,326)
Liabilities and Stockholders' Equity	324,710	204,785
Series Twenty One [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	131,345	116,749
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	3,000	3,000
ASSETS	134,345	119,749
LIABILITIES
Accounts payable and accrued expenses	5,000	5,000
Accounts payable affiliates (Note C)	1,426,064	1,383,089
Capital contributions payable	0	0
LIABILITIES	1,431,064	1,388,089
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(1,121,801)	(1,093,706)
General Partner	(174,918)	(174,634)
PARTNERS' CAPITAL (DEFICIT)	(1,296,719)	(1,268,340)
Liabilities and Stockholders' Equity	134,345	119,749
Series Twenty Two [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	125,587	98,564
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	125,587	98,564
LIABILITIES
Accounts payable and accrued expenses	3,750	0
Accounts payable affiliates (Note C)	2,796,762	2,892,033
Capital contributions payable	9,352	9,352
LIABILITIES	2,809,864	2,901,385
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(2,438,350)	(2,555,709)
General Partner	(245,927)	(247,112)
PARTNERS' CAPITAL (DEFICIT)	(2,684,277)	(2,802,821)
Liabilities and Stockholders' Equity	125,587	98,564
Series Twenty Three [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	159,736	118,542
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	159,736	118,542
LIABILITIES
Accounts payable and accrued expenses	3,750	0
Accounts payable affiliates (Note C)	2,189,031	2,549,950
Capital contributions payable	0	0
LIABILITIES	2,192,781	2,549,950
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(1,727,868)	(2,122,247)
General Partner	(305,177)	(309,161)
PARTNERS' CAPITAL (DEFICIT)	(2,033,045)	(2,431,408)
Liabilities and Stockholders' Equity	159,736	118,542
Series Twenty Four [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	812,995	890,715
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	812,995	890,715
LIABILITIES
Accounts payable and accrued expenses	3,000	3,000
Accounts payable affiliates (Note C)	0	0
Capital contributions payable	0	0
LIABILITIES	3,000	3,000
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	987,192	1,064,135
General Partner	(177,197)	(176,420)
PARTNERS' CAPITAL (DEFICIT)	809,995	887,715
Liabilities and Stockholders' Equity	812,995	890,715
Series Twenty Five [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	3,820,188	2,550,061
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	1,250	1,250
ASSETS	3,821,438	2,551,311
LIABILITIES
Accounts payable and accrued expenses	0	0
Accounts payable affiliates (Note C)	0	0
Capital contributions payable	0	0
LIABILITIES	0	0
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	4,040,668	2,783,242
General Partner	(219,230)	(231,931)
PARTNERS' CAPITAL (DEFICIT)	3,821,438	2,551,311
Liabilities and Stockholders' Equity	3,821,438	2,551,311
Series Twenty Six [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	3,012,761	2,510,330
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	3,012,761	2,510,330
LIABILITIES
Accounts payable and accrued expenses	19,960	4,960
Accounts payable affiliates (Note C)	0	0
Capital contributions payable	1,127	1,293
LIABILITIES	21,087	6,253
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	3,302,010	2,819,289
General Partner	(310,336)	(315,212)
PARTNERS' CAPITAL (DEFICIT)	2,991,674	2,504,077
Liabilities and Stockholders' Equity	3,012,761	2,510,330
Series Twenty Seven [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	1,079,820	1,049,687
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	6,500
ASSETS	1,079,820	1,056,187
LIABILITIES
Accounts payable and accrued expenses	52	0
Accounts payable affiliates (Note C)	0	44,238
Capital contributions payable	0	10,020
LIABILITIES	52	54,258
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	1,275,418	1,198,357
General Partner	(195,650)	(196,428)
PARTNERS' CAPITAL (DEFICIT)	1,079,768	1,001,929
Liabilities and Stockholders' Equity	1,079,820	1,056,187
Series Twenty Eight [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	5,318,053	515,862
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	1,250	2,817
ASSETS	5,319,303	518,679
LIABILITIES
Accounts payable and accrued expenses	8,855	7,500
Accounts payable affiliates (Note C)	0	706,182
Capital contributions payable	6,000	40,968
LIABILITIES	14,855	754,650
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	5,595,152	110,137
General Partner	(290,704)	(346,108)
PARTNERS' CAPITAL (DEFICIT)	5,304,448	(235,971)
Liabilities and Stockholders' Equity	5,319,303	518,679
Series Twenty Nine [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	514,618	224,155
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	514,618	224,155
LIABILITIES
Accounts payable and accrued expenses	14,448	0
Accounts payable affiliates (Note C)	3,784,578	3,583,859
Capital contributions payable	8,235	8,235
LIABILITIES	3,807,261	3,592,094
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(2,921,070)	(2,995,613)
General Partner	(371,573)	(372,326)
PARTNERS' CAPITAL (DEFICIT)	(3,292,643)	(3,367,939)
Liabilities and Stockholders' Equity	514,618	224,155
Series Thirty [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	308,632	253,948
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	500	500
ASSETS	309,132	254,448
LIABILITIES
Accounts payable and accrued expenses	9,000	0
Accounts payable affiliates (Note C)	1,807,174	1,690,813
Capital contributions payable	127,396	127,396
LIABILITIES	1,943,570	1,818,209
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(1,391,037)	(1,321,067)
General Partner	(243,401)	(242,694)
PARTNERS' CAPITAL (DEFICIT)	(1,634,438)	(1,563,761)
Liabilities and Stockholders' Equity	309,132	254,448
Series Thirty One [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	452,710	852,580
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	25,000	25,000
ASSETS	477,710	877,580
LIABILITIES
Accounts payable and accrued expenses	3,000	2,257
Accounts payable affiliates (Note C)	2,836,987	3,212,781
Capital contributions payable	66,294	66,294
LIABILITIES	2,906,281	3,281,332
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(2,025,027)	(2,000,456)
General Partner	(403,544)	(403,296)
PARTNERS' CAPITAL (DEFICIT)	(2,428,571)	(2,403,752)
Liabilities and Stockholders' Equity	477,710	877,580
Series Thirty Two [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	285,034	310,949
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	285,034	310,949
LIABILITIES
Accounts payable and accrued expenses	645	0
Accounts payable affiliates (Note C)	3,221,857	3,085,965
Capital contributions payable	3,486	3,486
LIABILITIES	3,225,988	3,089,451
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(2,505,181)	(2,344,354)
General Partner	(435,773)	(434,148)
PARTNERS' CAPITAL (DEFICIT)	(2,940,954)	(2,778,502)
Liabilities and Stockholders' Equity	285,034	310,949
Series Thirty Three [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	185,078	194,920
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	185,078	194,920
LIABILITIES
Accounts payable and accrued expenses	3,403	3,403
Accounts payable affiliates (Note C)	2,033,942	1,941,386
Capital contributions payable	69,154	69,154
LIABILITIES	2,106,499	2,013,943
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(1,676,427)	(1,575,053)
General Partner	(244,994)	(243,970)
PARTNERS' CAPITAL (DEFICIT)	(1,921,421)	(1,819,023)
Liabilities and Stockholders' Equity	185,078	194,920
Series Thirty Four [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	237,690	299,036
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	237,690	299,036
LIABILITIES
Accounts payable and accrued expenses	3,000	3,000
Accounts payable affiliates (Note C)	4,036,490	3,900,829
Capital contributions payable	0	0
LIABILITIES	4,039,490	3,903,829
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(3,463,392)	(3,268,355)
General Partner	(338,408)	(336,438)
PARTNERS' CAPITAL (DEFICIT)	(3,801,800)	(3,604,793)
Liabilities and Stockholders' Equity	237,690	299,036
Series Thirty Five [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	214,036	278,190
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	214,036	278,190
LIABILITIES
Accounts payable and accrued expenses	0	0
Accounts payable affiliates (Note C)	2,358,734	2,257,174
Capital contributions payable	0	0
LIABILITIES	2,358,734	2,257,174
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(1,841,226)	(1,677,169)
General Partner	(303,472)	(301,815)
PARTNERS' CAPITAL (DEFICIT)	(2,144,698)	(1,978,984)
Liabilities and Stockholders' Equity	214,036	278,190
Series Thirty Six [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	415,802	448,179
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	415,802	448,179
LIABILITIES
Accounts payable and accrued expenses	131,000	131,000
Accounts payable affiliates (Note C)	1,157,657	1,108,351
Capital contributions payable	0	0
LIABILITIES	1,288,657	1,239,351
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(685,463)	(604,597)
General Partner	(187,392)	(186,575)
PARTNERS' CAPITAL (DEFICIT)	(872,855)	(791,172)
Liabilities and Stockholders' Equity	415,802	448,179
Series Thirty Seven [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	323,320	305,167
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	323,320	305,167
LIABILITIES
Accounts payable and accrued expenses	0	0
Accounts payable affiliates (Note C)	2,300,795	2,147,147
Capital contributions payable	138,438	138,438
LIABILITIES	2,439,233	2,285,585
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(1,879,190)	(1,745,050)
General Partner	(236,723)	(235,368)
PARTNERS' CAPITAL (DEFICIT)	(2,115,913)	(1,980,418)
Liabilities and Stockholders' Equity	323,320	305,167
Series Thirty Eight [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	272,465	236,887
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	272,465	236,887
LIABILITIES
Accounts payable and accrued expenses	0	0
Accounts payable affiliates (Note C)	1,840,132	1,716,832
Capital contributions payable	0	0
LIABILITIES	1,840,132	1,716,832
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(1,333,706)	(1,246,861)
General Partner	(233,961)	(233,084)
PARTNERS' CAPITAL (DEFICIT)	(1,567,667)	(1,479,945)
Liabilities and Stockholders' Equity	272,465	236,887
Series Thirty Nine [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	161,560	144,094
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	161,560	144,094
LIABILITIES
Accounts payable and accrued expenses	5,000	0
Accounts payable affiliates (Note C)	1,650,499	1,547,899
Capital contributions payable	0	0
LIABILITIES	1,655,499	1,547,899
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(1,282,558)	(1,193,325)
General Partner	(211,381)	(210,480)
PARTNERS' CAPITAL (DEFICIT)	(1,493,939)	(1,403,805)
Liabilities and Stockholders' Equity	161,560	144,094
Series Forty [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	80,445	96,711
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	0	0
ASSETS	80,445	96,711
LIABILITIES
Accounts payable and accrued expenses	0	0
Accounts payable affiliates (Note C)	2,987,301	2,828,348
Capital contributions payable	102	102
LIABILITIES	2,987,403	2,828,450
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(2,652,945)	(2,479,478)
General Partner	(254,013)	(252,261)
PARTNERS' CAPITAL (DEFICIT)	(2,906,958)	(2,731,739)
Liabilities and Stockholders' Equity	80,445	96,711
Series Forty One [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	153,294	167,428
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	1,218	1,218
ASSETS	154,512	168,646
LIABILITIES
Accounts payable and accrued expenses	0	0
Accounts payable affiliates (Note C)	3,233,113	3,054,940
Capital contributions payable	100	100
LIABILITIES	3,233,213	3,055,040
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(2,798,745)	(2,608,361)
General Partner	(279,956)	(278,033)
PARTNERS' CAPITAL (DEFICIT)	(3,078,701)	(2,886,394)
Liabilities and Stockholders' Equity	154,512	168,646
Series Forty Two [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	315,027	266,762
Notes receivable	22,790	22,790
Acquisition costs, net	0	0
Other assets	51,003	51,003
ASSETS	388,820	340,555
LIABILITIES
Accounts payable and accrued expenses	0	0
Accounts payable affiliates (Note C)	2,257,998	2,071,473
Capital contributions payable	73,433	73,433
LIABILITIES	2,331,431	2,144,906
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(1,682,246)	(1,545,369)
General Partner	(260,365)	(258,982)
PARTNERS' CAPITAL (DEFICIT)	(1,942,611)	(1,804,351)
Liabilities and Stockholders' Equity	388,820	340,555
Series Forty Three [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	164,639	178,330
OTHER ASSETS
Cash and cash equivalents	321,530	303,384
Notes receivable	0	0
Acquisition costs, net	150,282	200,376
Other assets	104,989	85,341
ASSETS	741,440	767,431
LIABILITIES
Accounts payable and accrued expenses	0	0
Accounts payable affiliates (Note C)	2,778,313	2,548,228
Capital contributions payable	99,265	99,265
LIABILITIES	2,877,578	2,647,493
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(1,793,255)	(1,539,740)
General Partner	(342,883)	(340,322)
PARTNERS' CAPITAL (DEFICIT)	(2,136,138)	(1,880,062)
Liabilities and Stockholders' Equity	741,440	767,431
Series Forty Four [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	0	0
OTHER ASSETS
Cash and cash equivalents	7,582	38,362
Notes receivable	0	0
Acquisition costs, net	0	0
Other assets	89,683	0
ASSETS	97,265	38,362
LIABILITIES
Accounts payable and accrued expenses	0	0
Accounts payable affiliates (Note C)	1,907,961	1,642,751
Capital contributions payable	0	0
LIABILITIES	1,907,961	1,642,751
PARTNERS' CAPITAL (DEFICIT)
Units of beneficial interest of the limited partnership interest	(1,555,141)	(1,350,897)
General Partner	(255,555)	(253,492)
PARTNERS' CAPITAL (DEFICIT)	(1,810,696)	(1,604,389)
Liabilities and Stockholders' Equity	97,265	38,362
Series Forty Five [Member]
ASSETS
INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)	1,738,981	2,004,492
OTHER ASSETS
Cash and cash equivalents	107,498	126,153
Notes receivable	0	0
Acquisition costs, net	0	0

CONDENSED BALANCE SHEETS (USD $)

Dec. 31, 2014

Mar. 31, 2014

ASSETS

INVESTMENTS IN OPERATING PARTNERSHIPS (Note D)

$ 4,547,778

$ 5,328,701

OTHER ASSETS

Cash and cash equivalents

19,383,611

12,797,054

Notes receivable