Goodwill and Other Intangibles (Schedule of Goodwill) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill, Purchase Accounting Adjustments	$ 5,229
Goodwill [Roll Forward]
Carrying value, beginning balance	395,974	$ 390,745
Carrying value, ending balance	395,974
ACMI Services [Member]
Goodwill [Roll Forward]
Carrying value, beginning balance	234,571	234,571
Carrying value, ending balance	234,571
Other Segments [Member]
Goodwill [Line Items]
Goodwill, Purchase Accounting Adjustments	5,229
Goodwill [Roll Forward]
Carrying value, beginning balance		2,884
CAM [Member]
Goodwill [Roll Forward]
Carrying value, beginning balance	153,290	$ 153,290
Carrying value, ending balance	153,290
MRO Services [Member] [Member]
Goodwill [Roll Forward]
Carrying value, beginning balance	8,113
Carrying value, ending balance	$ 8,113