Consolidated Statements of Stockholders' Equity - USD ($)	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total	JHC [Member]
Balance at Dec. 31, 2016	$ 1,600	$ 14,780,100	$ 28,222,600	$ (504,100)	$ 42,500,200
Balance (in shares) at Dec. 31, 2016	1,566,699
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of shares	$ 0	0	0	$ (2,532,700)	$ (2,532,700)
Repurchase of shares (in shares)				(150,000)	(150,000)
Net income (loss)	0	0	7,399,200		$ 7,399,200
Balance at Dec. 31, 2017	$ 1,600	14,780,100	35,621,800	$ (3,036,800)	$ 47,366,700
Balance (in shares) at Dec. 31, 2017	1,416,699				1,416,699
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition of JHC by AeroCentury	$ 200	2,002,700	0	0	$ 2,002,900
Acquisition of JHC by AeroCentury (in shares)	129,217					129,217
Common stock shares held by JHC prior to the acquisition of JHC and retained as treasury stock	$ 0	0	0	(500)	(500)
Common stock shares held by JHC prior to the acquisition of JHC and retained as treasury stock (in shares)	(32)
Net income (loss)	$ 0	0	(8,081,200)	0	(8,081,200)
Balance at Dec. 31, 2018	$ 1,800	$ 16,782,800	$ 27,540,600	$ (3,037,300)	$ 41,287,900
Balance (in shares) at Dec. 31, 2018	1,545,884				1,545,884