Segment Information (Segment Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
REVENUES	$ 203,607	$ 253,211	$ 406,647	$ 491,128
Customer revenues	203,607	253,211	406,647	491,128
Depreciation and amortization expense	41,620	37,781	81,624	74,223
Inter-segment earnings eliminated	(1,031)	(5,958)	(4,356)	(6,820)
Net unallocated interest expense	(5,366)	(3,759)	10,728	7,307
Net gain (loss) on financial instruments	11,697	(67,649)	10,812	(65,780)
non-service components of retiree costs	2,045	(177)	4,090	(354)
Pre-tax earnings from continuing operations	29,911	(48,444)	50,839	(32,338)
Assets	1,517,474		1,517,474		$ 1,548,844
Deferred Revenue, Revenue Recognized	3,400		8,000
Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	203,607	253,211	406,647	491,128
Customer revenues	203,607	253,211	406,647	491,128
CAM [Member]
Segment Reporting Information [Line Items]
REVENUES	54,377	49,530	106,753	97,508
Customer revenues	54,377	49,530	106,753	97,508
Depreciation and amortization expense	30,540	26,253	59,465	50,554
Segment earnings (loss)	15,394	12,795	30,858	26,125
Net unallocated interest expense	(4,500)	(3,500)	(9,000)	(6,900)
Assets	1,214,986		1,214,986		1,192,890
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	38,016	32,380	73,903	63,162
Customer revenues	38,016	32,380	73,903	63,162
ACMI Services [Member]
Segment Reporting Information [Line Items]
REVENUES	119,606	144,499	238,980	289,448
Customer revenues	119,606	144,499	238,980	289,448
Depreciation and amortization expense	10,327	10,491	20,552	21,563
Segment earnings (loss)	991	258	4,932	(3,276)
Assets	190,309		190,309		189,379
ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	119,589	144,499	238,963	289,448
Customer revenues	119,589	144,499	238,963	289,448
MRO Services [Member]
Segment Reporting Information [Line Items]
REVENUES	45,794	66,336	98,517	106,674
Customer revenues	45,794	66,336	98,517	106,674
Depreciation and amortization expense	830	685	1,680	1,359
Segment earnings (loss)	1,321	11,103	5,783	14,291
Assets	99,129		99,129		87,177
MRO Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	29,069	31,159	60,009	56,576
Customer revenues	29,069	31,159	60,009	56,576
All other [Member]
Segment Reporting Information [Line Items]
REVENUES	19,730	50,172	39,013	99,040
Customer revenues	19,730	50,172	39,013	99,040
Depreciation and amortization expense	(77)	352	(73)	747
Segment earnings (loss)	2,749	1,400	5,330	3,863
Assets	13,050		13,050		$ 79,398
All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	16,933	45,173	33,772	81,942
Customer revenues	16,933	45,173	33,772	81,942
Significant Reconciling Items [Member]
Segment Reporting Information [Line Items]
Net unallocated interest expense	(838)	(216)	(1,657)	(387)
Non-operating charges from a non-consolidating affiliate	(2,417)	0	(4,953)	0
Eliminate inter-segment revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	(35,900)	(57,326)	(76,616)	(101,542)
Customer revenues	(35,900)	(57,326)	(76,616)	(101,542)
Customer Revenues [Member] | ACMI Services [Member]
Segment Reporting Information [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(48,135)		(97,309)
Customer Revenues [Member] | MRO Services [Member]
Segment Reporting Information [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	520		5,091
Customer Revenues [Member] | All other [Member]
Segment Reporting Information [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(45,749)		(97,096)
Customer Revenues [Member] | ACMI Services [Member]
Segment Reporting Information [Line Items]
REVENUES	167,724		336,272
Customer revenues	167,724		336,272
Customer Revenues [Member] | MRO Services [Member]
Segment Reporting Information [Line Items]
REVENUES	28,549		54,918
Customer revenues	28,549		54,918
Customer Revenues [Member] | All other [Member]
Segment Reporting Information [Line Items]
REVENUES	62,682		130,868
Customer revenues	62,682		130,868
Ground Services [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	16,159	44,650	32,314	80,949
Customer revenues	$ 16,159	$ 44,650	$ 32,314	$ 80,949