Income Taxes (Summary of Unrecognized Tax Benefits and Temporary Differences) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Unrecognized tax benefits
Balance at the beginning of the period	$ 191	$ 206	$ 274
Increases related to current year tax positions		4	4
Decreases due to tax positions expired	(9)	(19)	(72)
Balance at the end of the period	182	191	$ 206
Uncertain tax positions, reserved for tax exposure in Europe	0	0
Deferred tax assets:
Unearned lease revenue	1,094	1,754
State taxes	77	1,653
Reserves and allowances	1,187	2,531
Other accruals	3,795	643
Foreign tax credit	26	42
Net operating loss carry forward	39,996	29,874
Charitable contributions	38	22
Total deferred tax assets	46,213	36,519
Less: valuation allowance	(652)	(806)
Net deferred tax assets	45,561	35,713
Deferred tax liabilities:
Depreciation and impairment on aircraft engines and equipment	(133,453)	(114,347)
Other deferred tax assets (liabilities)	(2,365)	437
Net deferred tax liabilities	(135,818)	(113,910)
Other comprehensive income, deferred tax asset	(28)	(83)
Net deferred tax liabilities	(90,285)	$ (78,280)
Expired operating loss carryforwards	5,500
Valuation allowance of net operating loss	$ 700
Statutory federal income tax expense (as a percent)	21.00%	35.00%
Provisional amount	$ 43,600
Federal
Deferred tax assets:
Alternative minimum tax credit		$ 400
Deferred tax liabilities:
Operating loss carryforwards	188,300
Federal | Minimum
Deferred tax liabilities:
Alternative minimum tax credit period		2 years
Federal | Maximum
Deferred tax liabilities:
Alternative minimum tax credit period		4 years
State
Deferred tax liabilities:
Operating loss carryforwards	$ 800