Segment Information (Segment Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
REVENUES	$ 204,919	$ 254,101	$ 611,566	$ 745,229
Customer revenues	204,919	254,101	611,566	745,229
Depreciation and amortization expense	43,201	37,605	124,825	111,828
Inter-segment earnings eliminated	(2,420)	(3,285)	(6,776)	(10,105)
Net unallocated interest expense	(5,608)	(4,351)	(16,336)	(11,658)
Net gain (loss) on financial instruments	17,895	(34,433)	28,707	(100,213)
non-service components of retiree costs	2,045	(5,529)	6,135	(5,883)
Pre-tax earnings from continuing operations	38,579	(20,769)	89,418	(53,107)
Assets	1,553,068		1,553,068		$ 1,548,844
Deferred Revenue, Revenue Recognized	4,800		8,800
Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	204,919	254,101	611,566	745,229
Customer revenues	204,919	254,101	611,566	745,229
CAM [Member]
Segment Reporting Information [Line Items]
REVENUES	58,786	58,465	165,539	155,973
Customer revenues	58,786	58,465	165,539	155,973
Depreciation and amortization expense	31,590	26,829	91,055	77,383
Segment earnings (loss)	19,034	19,445	49,892	45,570
Net unallocated interest expense	(4,700)	(4,000)	(13,700)	(10,900)
Assets	1,246,833		1,246,833		1,192,890
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	41,366	40,940	115,270	104,102
Customer revenues	41,366	40,940	115,270	104,102
ACMI Services [Member]
Segment Reporting Information [Line Items]
REVENUES	116,224	146,943	355,204	436,391
Customer revenues	116,224	146,943	355,204	436,391
Depreciation and amortization expense	10,950	9,805	31,502	31,368
Segment earnings (loss)	61	300	4,993	(2,976)
Assets	180,382		180,382		189,379
ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	116,209	146,938	355,172	436,386
Customer revenues	116,209	146,938	355,172	436,386
MRO Services [Member]
Segment Reporting Information [Line Items]
REVENUES	46,879	39,928	145,125	146,602
Customer revenues	46,879	39,928	145,125	146,602
Depreciation and amortization expense	840	680	2,520	2,039
Segment earnings (loss)	2,332	2,514	8,115	16,805
Assets	96,277		96,277		87,177
MRO Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	27,227	13,916	87,236	70,492
Customer revenues	27,227	13,916	87,236	70,492
All other [Member]
Segment Reporting Information [Line Items]
REVENUES	22,598	54,542	61,611	153,582
Customer revenues	22,598	54,542	61,611	153,582
Depreciation and amortization expense	(179)	291	(252)	1,038
Segment earnings (loss)	3,139	1,432	8,469	5,295
Assets	29,576		29,576		$ 79,398
All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	20,117	52,307	53,888	134,249
Customer revenues	20,117	52,307	53,888	134,249
Significant Reconciling Items [Member]
Segment Reporting Information [Line Items]
Net unallocated interest expense	(860)	(268)	(2,517)	(655)
Non-operating charges from a non-consolidating affiliate	(2,647)	(945)	(7,600)	(945)
Eliminate inter-segment revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	(39,568)	(45,777)	(115,913)	(147,319)
Customer revenues	(39,568)	(45,777)	(115,913)	(147,319)
Customer Revenues [Member] | ACMI Services [Member]
Segment Reporting Information [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(47,657)		(144,967)
Customer Revenues [Member] | MRO Services [Member]
Segment Reporting Information [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	1,908		6,999
Customer Revenues [Member] | All other [Member]
Segment Reporting Information [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(40,836)		(137,932)
Customer Revenues [Member] | ACMI Services [Member]
Segment Reporting Information [Line Items]
REVENUES	163,866		500,139
Customer revenues	163,866		500,139
Customer Revenues [Member] | MRO Services [Member]
Segment Reporting Information [Line Items]
REVENUES	25,319		80,237
Customer revenues	25,319		80,237
Customer Revenues [Member] | All other [Member]
Segment Reporting Information [Line Items]
REVENUES	60,953		191,820
Customer revenues	60,953		191,820
Ground Services [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	19,540	51,728	51,854	132,678
Customer revenues	$ 19,540	$ 51,728	$ 51,854	$ 132,678