Document And Entity Information	12 Months Ended
	Dec. 31, 2019 USD ($) shares
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Registrant Name	BCTC V ASSIGNOR CORP
Entity Central Index Key	0001267426
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Public Float | $	$ 0
Entity Common Stock, Shares Outstanding | shares	1,000
Entity Shell Company	true
Entity Emerging Growth Company	false
Entity Small Business	true