Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Nov. 12, 2020
Cover [Abstract]
Entity Registrant Name	AEROCENTURY CORP
Entity Central Index Key	0001036848
Document Type	10-Q
Document Period End Date	Sep. 30, 2020
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Is Entity's Reporting Status Current?	Yes
Is Entity Emerging Growth Company?	false
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Incorporation State Country Code	DE
Entity File Number	001-13387
Entity Common Stock, Shares Outstanding		1,545,884
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2020