Segment Information (Narrative) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) segments	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
REVENUES	$ 403,351	$ 366,073	$ 334,576	$ 348,183	$ 280,779	$ 204,919	$ 203,607	$ 203,040	$ 1,452,183	$ 892,345	$ 1,068,200
Deferred Revenue, Revenue Recognized									2,800	9,300
Deferred Revenue	3,000				$ 3,100				$ 3,000	3,100
Number of reportable segments (in segments) | segments									2
Interest expense									$ 66,644	28,799	17,023
Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES									1,452,183	892,345	1,068,200
ACMI Services [Member]
Segment Reporting Information [Line Items]
REVENUES									1,078,288	548,839	614,741
Interest expense									24,950	6,269	810
Property, Plant and Equipment, Additions									87,200
ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES										548,804	614,721
CAM [Member]
Segment Reporting Information [Line Items]
REVENUES									285,276	228,956	209,213
Interest expense									38,300	21,819	15,585
Property, Plant and Equipment, Additions									368,800
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES										156,516	140,434
Geographic Distribution, Foreign [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES									716,900	231,800	$ 170,100
Flight Equipment [Member]
Segment Reporting Information [Line Items]
Operating Leases, Future Minimum Payments Receivable, Current	186,800								186,800
Operating Leases, Future Minimum Payments Receivable, in Two Years	178,200								178,200
Operating Leases, Future Minimum Payments Receivable, in Three Years	152,000								152,000
Operating Leases, Future Minimum Payments Receivable, in Four Years	110,100								110,100
Operating Leases, Future Minimum Payments Receivable, in Five Years	75,500								75,500
Operating Leases, Future Minimum Payments Receivable, Thereafter	$ 186,200								$ 186,200
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES										(357,295)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES										(194,308)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES										$ 0