Segment Information (Segment Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Operating Expenses	$ 325,253	$ 354,616	$ 644,482	$ 694,086
REVENUES	409,872	377,794	785,960	767,071
Customer revenues	409,872	377,794	785,960	767,071
Depreciation and amortization expense	75,633	68,291	146,684	137,633
Net unallocated interest expense	(15,021)	(16,045)	(29,543)	(32,368)
Net gain (loss) on financial instruments	35,703	(109,723)	45,175	(2,679)
Pre-tax earnings from continuing operations	104,226	(106,193)	159,328	34,581
Assets	3,210,854		3,210,854		$ 3,001,745
Income Tax Expense (Benefit)		(1,031)	37,169	6,010
Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component	4,456	2,898	8,913	5,796
Net earnings from continuing operations	79,869	(105,162)	122,159	28,571
Income Tax (Expense) Benefit, Continuing Operations, Government Grants	38,274	9,821	66,304	9,821
Asset Impairment Charges	0	(39,075)	0	(39,075)
Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	409,872	377,794	785,960	767,071
Customer revenues	409,872	377,794	785,960	767,071
ACMI Services [Member]
Segment Reporting Information [Line Items]
REVENUES	273,301	287,604	520,432	571,769
Customer revenues	273,301	287,604	520,432	571,769
Depreciation and amortization expense	24,768	25,384	47,749	50,696
Segment earnings (loss)	44,762	29,505	66,021	47,883
Net unallocated interest expense	(4,473)	(5,645)	(8,996)	(10,946)
Assets	829,365		829,365		811,516
ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	273,295	287,595	520,422	571,756
Customer revenues	273,295	287,595	520,422	571,756
All other [Member]
Segment Reporting Information [Line Items]
REVENUES	97,236	77,056	190,934	157,092
Customer revenues	97,236	77,056	190,934	157,092
Depreciation and amortization expense	853	883	1,928	1,866
Segment earnings (loss)	3,161	(2,244)	3,550	(2,191)
Assets	182,227		182,227		152,601
All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	69,901	40,240	138,062	98,620
Customer revenues	69,901	40,240	138,062	98,620
CAM [Member]
Segment Reporting Information [Line Items]
REVENUES	88,594	74,870	171,871	149,033
Customer revenues	88,594	74,870	171,871	149,033
Depreciation and amortization expense	50,012	42,024	97,007	85,071
Segment earnings (loss)	22,554	19,640	44,016	35,460
Net unallocated interest expense	(9,669)	(9,707)	(18,895)	(19,962)
Assets	2,199,262		2,199,262		$ 2,037,628
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	66,676	49,959	127,476	96,695
Customer revenues	66,676	49,959	127,476	96,695
Significant Reconciling Items [Member]
Segment Reporting Information [Line Items]
Net unallocated interest expense	(870)	(681)	(1,624)	(1,336)
Non-operating charges from a non-consolidating affiliate	965	(6,513)	(218)	(9,277)
Eliminate inter-segment revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	(49,259)	(61,736)	(97,277)	(110,823)
Customer revenues	(49,259)	(61,736)	(97,277)	(110,823)
Accounting Standards Update 2014-09 [Member]
Segment Reporting Information [Line Items]
Income Tax Expense (Benefit)	(24,357)
Accounting Standards Update 2014-09 [Member] | Ground Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	28,791	18,851	62,839	52,686
Customer revenues	28,791	18,851	62,839	52,686
Accounting Standards Update 2014-09 [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	69,901	40,240	138,062	98,620
Customer revenues	69,901	40,240	138,062	98,620
Accounting Standards Update 2014-09 [Member] | Ground Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	29,022	16,003	52,482	30,611
Customer revenues	29,022	16,003	52,482	30,611
Accounting Standards Update 2014-09 [Member] | All Other non MRO or Ground Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	12,088	5,386	22,741	15,323
Customer revenues	$ 12,088	$ 5,386	$ 22,741	$ 15,323