Segment Information (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) segments	Sep. 30, 2017 USD ($)
Segment Reporting Information [Line Items]
Deferred Revenue, Revenue Recognized	$ 4,800		$ 8,800
REVENUES	204,919	$ 254,101	$ 611,566	$ 745,229
Number of reportable segments (in segments) | segments			3
Interest expense	5,608	4,351	$ 16,336	11,658
Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	204,919	254,101	611,566	745,229
ACMI Services [Member]
Segment Reporting Information [Line Items]
REVENUES	116,224	146,943	355,204	436,391
ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	116,209	146,938	355,172	436,386
Other Segments [Member]
Segment Reporting Information [Line Items]
REVENUES	22,598	54,542	61,611	153,582
Other Segments [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	20,117	52,307	53,888	134,249
CAM [Member]
Segment Reporting Information [Line Items]
REVENUES	58,786	58,465	165,539	155,973
Interest expense	4,700	4,000	13,700	10,900
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	41,366	40,940	115,270	104,102
Ground Services [Member] | Other Segments [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	$ 19,540	$ 51,728	$ 51,854	$ 132,678