Segment Information (Segment Reconciliation) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Customer revenues	$ 143,593	$ 143,279
Depreciation and amortization expense	24,979	20,920
Net unallocated interest expense	(3,823)	(3,132)
Net gain on derivative instruments	299	290
Pre-tax earnings from continuing operations	10,331	13,592
Assets	1,028,045		1,033,139
Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	143,593	143,279
CAM [Member]
Segment Reporting Information [Line Items]
Customer revenues	40,635	38,969
Depreciation and amortization expense	18,345	14,516
Segment earnings (loss)	14,440	16,873
Net unallocated interest expense	(3,300)	(2,600)
Assets	792,220		808,987
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	18,413	18,336
ACMI Services [Member]
Segment Reporting Information [Line Items]
Customer revenues	108,596	113,051
Depreciation and amortization expense	6,835	6,138
Segment earnings (loss)	(7,046)	(5,404)
Net unallocated interest expense	(100)	(200)
Assets	146,065		141,664
ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	108,596	111,315
All other [Member]
Segment Reporting Information [Line Items]
Customer revenues	26,808	26,254
Depreciation and amortization expense	(201)	266
Segment earnings (loss)	3,017	2,181
Assets	89,137		82,194
All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	16,584	13,628
Discontinued operations [Member]
Segment Reporting Information [Line Items]
Assets	623		294
Significant Reconciling Items [Member]
Segment Reporting Information [Line Items]
Net unallocated interest expense	(379)	(348)
Eliminate inter-segment revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	$ (32,446)	$ (34,995)