Goodwill and Other Intangibles (Schedule Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Finite and Indefinite-lived Intangible Assets by Major Class [Line Items]
Incentive to Lessee		$ 76,458	$ 80,684
Amortization of Lease Incentives	$ (4,226)
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	(290)
Carrying value at end of period	4,298	$ 4,008	$ 4,298
Carrying value at end of period	7,008
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