Goodwill and Other Intangibles (Schedule Intangible Assets) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Finite and Indefinite-lived Intangible Assets by Major Class [Line Items]
Incentive to Lessee		$ 68,006	$ 80,684
Amortization of Lease Incentives	$ (12,678)
Finite and Indefinite-lived Intangible Assets [Roll Forward]
Carrying value at beginning of period	4,298
Carrying value at beginning of period	7,298
Amortization expense	(867)
Carrying value at end of period	4,298	$ 3,431	$ 4,298
Carrying value at end of period	6,431
ACMI Services [Member] | Airline Certificates [Member]
Finite and Indefinite-lived Intangible Assets [Roll Forward]
Carrying value at beginning of period	3,000
Amortization expense	0
Carrying value at end of period	$ 3,000