Segment Information (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) segments	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
REVENUES	$ 465,955	$ 404,146	$ 1,251,915	$ 1,171,217
Deferred Revenue, Revenue Recognized	1,100	4,700	2,900	2,800
Deferred Revenue	2,700		$ 2,700		$ 3,000
Number of reportable segments (in segments) | segments			2
Interest expense	14,459	15,440	$ 44,002	47,808
Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	465,955	404,146	1,251,915	1,171,217
ACMI Services [Member]
Segment Reporting Information [Line Items]
REVENUES	330,906	300,189	851,338	871,958
Interest expense	4,672	4,803	13,668	15,749
Property, Plant and Equipment, Additions			69,300
ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	330,903	300,189	851,325	871,945
CAM [Member]
Segment Reporting Information [Line Items]
REVENUES	92,931	76,268	264,802	225,301
Interest expense	9,408	9,747	28,303	29,709
Property, Plant and Equipment, Additions			358,100
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	71,070	$ 51,409	198,546	$ 148,104
Flight Equipment [Member]
Segment Reporting Information [Line Items]
Operating Leases, Future Minimum Payments Receivable, Current	67,400		67,400		222,400
Operating Leases, Future Minimum Payments Receivable, in Two Years	240,100		240,100		195,500
Operating Leases, Future Minimum Payments Receivable, in Three Years	196,100		196,100		150,500
Operating Leases, Future Minimum Payments Receivable, in Four Years	145,500		145,500		99,800
Operating Leases, Future Minimum Payments Receivable, in Five Years	132,400		132,400		90,700
Operating Leases, Future Minimum Payments Receivable, Thereafter	$ 372,100		$ 372,100		$ 202,200