Segment Information (Segment Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Operating Expenses	$ 366,195	$ 330,176	$ 1,010,677	$ 1,024,262
REVENUES	465,955	404,146	1,251,915	1,171,217
Customer revenues	465,955	404,146	1,251,915	1,171,217
Depreciation and amortization expense	77,751	67,974	224,435	205,607
Net unallocated interest expense	(14,459)	(15,440)	(44,002)	(47,808)
Net gain (loss) on financial instruments	(7,378)	(53,393)	37,797	(56,072)
Pre-tax earnings from continuing operations	81,241	5,642	240,569	40,223
Assets	3,222,174		3,222,174		$ 3,001,745
Income Tax Expense (Benefit)		11,387	56,047	17,397
Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component	4,457	2,897	13,370	8,693
Net earnings from continuing operations	62,363	(5,745)	184,522	22,826
Income Tax (Expense) Benefit, Continuing Operations, Government Grants	30,322	21,726	96,626	31,547
Asset Impairment Charges	0	0	0	(39,075)
Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	465,955	404,146	1,251,915	1,171,217
Customer 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
Customer revenues	330,906	300,189	851,338	871,958
Depreciation and amortization expense	25,649	25,336	73,398	76,032
Segment earnings (loss)	58,225	40,363	124,246	88,246
Net unallocated interest expense	(4,672)	(4,803)	(13,668)	(15,749)
Assets	814,195		814,195		811,516
ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	330,903	300,189	851,325	871,945
Customer revenues	330,903	300,189	851,325	871,945
All other [Member]
Segment Reporting Information [Line Items]
REVENUES	90,292	82,281	281,226	239,373
Customer revenues	90,292	82,281	281,226	239,373
Depreciation and amortization expense	719	1,217	2,647	3,083
Segment earnings (loss)	(1,047)	(724)	2,503	(2,915)
Assets	169,341		169,341		152,601
All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	63,982	52,548	202,044	151,168
Customer revenues	63,982	52,548	202,044	151,168
CAM [Member]
Segment Reporting Information [Line Items]
REVENUES	92,931	76,268	264,802	225,301
Customer revenues	92,931	76,268	264,802	225,301
Depreciation and amortization expense	51,383	41,421	148,390	126,492
Segment earnings (loss)	28,502	19,781	72,518	55,241
Net unallocated interest expense	(9,408)	(9,747)	(28,303)	(29,709)
Assets	2,238,638		2,238,638		$ 2,037,628
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	71,070	51,409	198,546	148,104
Customer revenues	71,070	51,409	198,546	148,104
Significant Reconciling Items [Member]
Segment Reporting Information [Line Items]
Net unallocated interest expense	(371)	(797)	(1,995)	(2,133)
Non-operating charges from a non-consolidating affiliate	(1,147)	(2,485)	(1,365)	(11,762)
Eliminate inter-segment revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	(48,174)	(54,592)	(145,451)	(165,415)
Customer revenues	(48,174)	(54,592)	(145,451)	(165,415)
Accounting Standards Update 2014-09 [Member]
Segment Reporting Information [Line Items]
Income Tax Expense (Benefit)	(18,878)
Accounting Standards Update 2014-09 [Member] | Ground Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	28,513	26,063	91,352	78,749
Customer revenues	28,513	26,063	91,352	78,749
Accounting Standards Update 2014-09 [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	63,982	52,548	202,044	151,168
Customer revenues	63,982	52,548	202,044	151,168
Accounting Standards Update 2014-09 [Member] | Ground Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	22,928	19,887	75,410	50,498
Customer revenues	22,928	19,887	75,410	50,498
Accounting Standards Update 2014-09 [Member] | All Other non MRO or Ground Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	12,541	6,598	35,282	21,921
Customer revenues	$ 12,541	$ 6,598	$ 35,282	$ 21,921