Segment Information (Entity-Wide Disclosures) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Customer revenues	$ 156,963	$ 140,877	$ 138,904	$ 143,279	$ 154,552	$ 153,826	$ 153,554	$ 145,506	$ 580,023	$ 607,438	$ 730,133
Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues									580,023	607,438	730,133
All other [Member]
Segment Reporting Information [Line Items]
Customer revenues									117,292	112,343	105,284
All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues									63,915	55,117	57,391
Aircraft maintenance and part sales [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues									23,175	21,669	25,845
Mail handling services [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues									30,117	23,671	21,613
Facility and ground equipment maintenance [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues									10,030	8,304	8,465
Other [Member] | All other [Member] | Customer Revenues [Member]
Segment Reporting Information [Line Items]
Customer revenues									$ 593	$ 1,473	$ 1,468