Income Taxes - Summary of Unrecognized Tax Benefits and Temporary Differences (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Unrecognized tax benefits
Balance at the beginning of the period	$ 182,000	$ 191,000
Increases related to current year tax positions	250,000
Decreases due to tax positions expired	(162,000)	(9,000)
Balance at the end of the period	270,000	182,000
Uncertain tax positions, reserved for tax exposure in Europe	200,000	0
Deferred tax assets:
Unearned lease revenue	1,277,000	1,094,000
State taxes	152,000	77,000
Reserves and allowances	1,988,000	1,187,000
Other accruals	4,974,000	3,795,000
Foreign tax credit	19,000	26,000
Lease liability	271,000	0
Net operating loss carry forward	12,091,000	39,996,000
Charitable contributions	57,000	38,000
Total deferred tax assets	20,829,000	46,213,000
Less: valuation allowance	(153,000)	(652,000)
Net deferred tax assets	20,676,000	45,561,000
Deferred tax liabilities:
Depreciation and impairment on aircraft engines and equipment	(118,595,000)	(133,453,000)
Inventory	(2,350,000)	0
Right of use liability	(6,900,000)	0
Other deferred tax assets (liabilities)	(4,198,000)	(2,365,000)
Net deferred tax liabilities	(132,043,000)	(135,818,000)
Other comprehensive loss deferred tax liability	949,000
Other comprehensive loss deferred tax liability		28,000
Net deferred tax liabilities	(110,418,000)	$ (90,285,000)
Valuation allowance of net operating loss	200,000
Federal
Deferred tax liabilities:
Operating loss carryforwards	55,800,000
State
Deferred tax liabilities:
Operating loss carryforwards	$ 400,000