Organization and Summary of Significant Accounting Policies (Details)		3 Months Ended		6 Months Ended
	Aug. 31, 2016 Subsidiary	Jun. 30, 2018 USD ($) Aircraft	Jun. 30, 2017 USD ($) Aircraft	Jun. 30, 2018 USD ($) Aircraft Lease	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Organization and Summary of Significant Accounting Policies [Abstract]
Number of wholly owned subsidiaries | Subsidiary	2
Finance Leases [Abstract]
Impairment charge		$ 298,200	$ 454,300	$ 298,200	$ 454,300
Notes payable and accrued interest		147,642,500		$ 147,642,500		$ 145,598,200
Number of aircraft with sales type finance leases | Aircraft				6
Number of aircraft with direct financing leases | Aircraft				3
Number of finance leases | Lease				9
Interest earned on finance lease		$ 361,300	432,300	$ 740,400	$ 757,700
Recent Accounting Pronouncements [Abstract]
Federal corporate tax rate		21.00%
SPE Financing [Member]
Finance Leases [Abstract]
Notes payable and accrued interest		$ 11,403,000		11,403,000		13,535,300
Credit Facility [Member]
Finance Leases [Abstract]
Notes payable and accrued interest		137,723,000		137,723,000		134,278,900
Recurring [Member]
Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis [Abstract]
Money market funds included in cash and cash equivalents		2,154,400		2,154,400		6,151,900
Liabilities recorded at fair value		0		$ 0		$ 0
Aircraft [Member] | Held for Lease [Member]
Finance Leases [Abstract]
Impairment charge		$ 298,200	$ 454,300
Number of assets held for lease | Aircraft		1	1