Award Timing Disclosure	12 Months Ended
Award Timing Disclosure	Dec. 31, 2024
Award Timing Disclosures [Line Items]
Award Timing MNPI Disclosure	The Assignor Limited Partner currently does not plan to grant equity awards, including stock options, to officers, directors, employees, or service providers; accordingly, the Assignor Limited Partner does not have a formal policy in place with regard to the timing of awards of options in relation to the disclosure of material nonpublic information. The Assignor Limited Partner has not timed the disclosure of material nonpublic information to affect the value of executive compensation.
Award Timing Method	the Assignor Limited Partner does not have a formal policy in place with regard to the timing of awards of options in relation to the disclosure of material nonpublic information.
Award Timing MNPI Considered	false
Award Timing, How MNPI Considered	The Assignor Limited Partner has not timed the disclosure of material nonpublic information to affect the value of executive compensation
MNPI Disclosure Timed for Compensation Value	false

BCTC IV ASSIGNOR CORP 10-K