Segment Information (Entity-Wide Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Customer revenues	$ 254,101	$ 193,261	$ 745,229	$ 547,195
Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	254,101	193,261	745,229	547,195
CAM [Member]
Segment Reporting Information [Line Items]
Customer revenues	58,465	46,346	155,973	145,511
CAM [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	40,940	27,920	104,102	86,068
All other [Member]
Segment Reporting Information [Line Items]
Customer revenues	94,470	65,328	300,184	177,592
All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	66,223	36,639	204,741	103,324
Mailing Handling Services [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	48,283	23,502	123,564	62,553
Aircraft Maintenance and Part Sales [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	13,915	8,958	70,492	30,217
Facility and Ground Equipment Maintenance [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	3,625	3,780	9,528	9,281
Other Activity [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues	$ 400	$ 399	$ 1,157	$ 1,273