Segment Information (Segment Reconciliation) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Customer revenues	$ 149,618	$ 138,904	$ 293,211	$ 282,183
Depreciation and amortization expense	27,142	21,765	52,121	42,685
Net unallocated interest expense	(3,481)	(3,554)	(7,304)	6,686
Net gain on derivative instruments	31	452	330	742
Unrealized Gain (Loss) on Derivatives			330	742
Pre-tax earnings from continuing operations	14,691	11,085	25,022	24,677
Assets	1,024,484		1,024,484		1,033,139
Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	149,618	138,904	293,211	282,183
CAM [Member]
Segment Reporting Information [Line Items]
Customer revenues	40,590	39,362	81,225	78,331
Depreciation and amortization expense	20,328	14,803	38,673	29,319
Segment earnings (loss)	10,667	17,214	25,107	34,087
Net unallocated interest expense	(3,000)	(3,300)	(6,300)	(5,900)
Assets	776,655		776,655		808,987
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	17,839	17,845	36,253	36,181
ACMI Services [Member]
Segment Reporting Information [Line Items]
Customer revenues	111,304	106,604	219,900	217,920
Depreciation and amortization expense	7,191	6,692	14,026	12,830
Segment earnings (loss)	309	(9,093)	(6,737)	(14,497)
Net unallocated interest expense	(100)	(100)	(200)	(300)
Assets	156,466		156,466		141,664
ACMI Services [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	111,304	106,604	219,900	217,920
All other [Member]
Segment Reporting Information [Line Items]
Customer revenues	36,493	26,951	63,301	53,205
Depreciation and amortization expense	(377)	270	(578)	536
Segment earnings (loss)	4,108	2,607	7,125	4,788
Assets	90,411		90,411		82,194
All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	20,475	14,455	37,058	28,082
Discontinued operations [Member]
Segment Reporting Information [Line Items]
Assets	952		952		294
Significant Reconciling Items [Member]
Segment Reporting Information [Line Items]
Net unallocated interest expense	(424)	(95)	(803)	(443)
Eliminate inter-segment revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	$ (38,769)	$ (34,013)	$ (71,215)	$ (67,273)