Segment Information (Narrative) (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018 USD ($)	Mar. 31, 2018 segments	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)
Segment Reporting Information [Line Items]
Deferred Revenue, Revenue Recognized	$ 3,400			$ 8,000
REVENUES	203,607		$ 253,211	406,647	$ 491,128
Number of reportable segments (in segments) | segments		3
Interest expense	5,366		3,759	(10,728)	(7,307)
Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	203,607		253,211	406,647	491,128
ACMI Services [Member]
Segment Reporting Information [Line Items]
REVENUES	119,606		144,499	238,980	289,448
ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	119,589		144,499	238,963	289,448
Other Segments [Member]
Segment Reporting Information [Line Items]
REVENUES	19,730		50,172	39,013	99,040
Other Segments [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	16,933		45,173	33,772	81,942
CAM [Member]
Segment Reporting Information [Line Items]
REVENUES	54,377		49,530	106,753	97,508
Interest expense	4,500		3,500	9,000	6,900
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	38,016		32,380	73,903	63,162
Ground Services [Member] | Other Segments [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	$ 16,159		$ 44,650	$ 32,314	$ 80,949