FLEET TRANSITION EXPENSES (DETAILS) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	$ 0	$ 2.0	$ 0	$ 38.9
Horizon Fleet Transition - CRJ-700 [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	0	(2.6)	0	28.3
Horizon Fleet Transition - Q200 [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	$ 0	$ 4.6	$ 0	$ 10.6

The aggregate amount provided for estimated restructuring charges, remediation costs, and asset impairment loss during an accounting period. Generally, these items are either unusual or infrequent, but not both (in which case they would be extraordinary items).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.3)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration