Commitments and Contingencies - Sale Leaseback Transactions Aircraft (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2014 aircraft
Commitments and Contingencies Disclosure [Abstract]
Number of aircrafts delivered	3
Aircraft [Member]
Sale Leaseback Transaction [Line Items]
Number of aircraft entered into sale and leaseback agreement	3
Sale leaseback transaction on aircraft, net deferred gain (loss)	$ (1.0)
Sale leaseback transaction on aircraft, refund in pre-delivery deposits	$ 16.0

The portion of the gain that will be recorded as income or a reduction in rent expense in future periods less amounts recognized in the current period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 40

-Section 35

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35688829&loc=d3e50609-112754

Name:	us-gaap_SaleLeasebackTransactionDeferredGainNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant