INVESTMENTS IN OPERATING PARTNERSHIPS - Additional Information (Details)	3 Months Ended
Jun. 30, 2022 USD ($)
Series 29
INVESTMENT IN OPERATING PARTNERSHIPS
Write-off of capital contribution payable	$ 785

Amount of write off of capital contribution payable.

No definition available.

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Namespace Prefix:	bctciv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration