Segment Information (Segment Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
REVENUES	$ 203,040	$ 237,917
Customer revenues	203,040	237,917
Depreciation and amortization expense	40,004	36,442
Inter-segment earnings eliminated	(3,325)	(862)
Net unallocated interest expense	(5,362)	(3,548)
Net gain (loss) on financial instruments	(885)	1,869
non-service components of retiree costs	2,045	(177)
Pre-tax earnings from continuing operations	20,928	16,106
Assets	1,567,503		$ 1,548,844
Deferred Revenue, Revenue Recognized	5,900
Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	203,040	237,917
Customer revenues	203,040	237,917
CAM [Member]
Segment Reporting Information [Line Items]
REVENUES	52,376	47,978
Customer revenues	52,376	47,978
Depreciation and amortization expense	28,925	24,301
Segment earnings (loss)	15,464	13,330
Net unallocated interest expense	(4,500)	(3,300)
Assets	1,201,208		1,192,890
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	35,887	30,782
Customer revenues	35,887	30,782
ACMI Services [Member]
Segment Reporting Information [Line Items]
REVENUES	119,374	144,949
Customer revenues	119,374	144,949
Depreciation and amortization expense	10,225	11,072
Segment earnings (loss)	3,941	(3,534)
Assets	195,790		189,379
ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	119,374	144,949
Customer revenues	119,374	144,949
MRO Services [Member]
Segment Reporting Information [Line Items]
REVENUES	52,723	40,338
Customer revenues	52,723	40,338
Depreciation and amortization expense	850	674
Segment earnings (loss)	4,462	3,188
Assets	96,451		87,177
MRO Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	30,939	25,417
Customer revenues	30,939	25,417
All other [Member]
Segment Reporting Information [Line Items]
REVENUES	19,283	48,868
Customer revenues	19,283	48,868
Depreciation and amortization expense	4	395
Segment earnings (loss)	2,581	2,463
Assets	74,054		$ 79,398
All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	16,840	36,769
Customer revenues	16,840	36,769
Significant Reconciling Items [Member]
Segment Reporting Information [Line Items]
Net unallocated interest expense	(819)	(171)
Non-operating charges from a non-consolidating affiliate	(2,536)	0
Eliminate inter-segment revenues [Member]
Segment Reporting Information [Line Items]
REVENUES	(40,716)	(44,216)
Customer revenues	(40,716)	$ (44,216)
Customer Revenues [Member] | ACMI Services [Member]
Segment Reporting Information [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(49,175)
Customer Revenues [Member] | MRO Services [Member]
Segment Reporting Information [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	5,460
Customer Revenues [Member] | All other [Member]
Segment Reporting Information [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(51,347)
Customer Revenues [Member] | ACMI Services [Member]
Segment Reporting Information [Line Items]
REVENUES	168,549
Customer revenues	168,549
Customer Revenues [Member] | MRO Services [Member]
Segment Reporting Information [Line Items]
REVENUES	25,479
Customer revenues	25,479
Customer Revenues [Member] | All other [Member]
Segment Reporting Information [Line Items]
REVENUES	68,187
Customer revenues	$ 68,187