Face/par value in contract for future debt financing commitments

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of Aircraft with Secured Debt Financing Commitments Scheduled for Delivery

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Number of Delivered Aircraft with Secured Debt Financing Commitments

+ References

No definition available.

+ Details

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- Definition

Number of Facility Agreements

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Number of Trusts

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Line-of-Credit Arrangement
-URI http://asc.fasb.org/extlink&oid=6517033

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3291-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

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

- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Debt and Other Obligations - Narrative (Details) $ in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2015 USD ($) aircraft trust	Dec. 31, 2016 USD ($) aircraft	Dec. 31, 2015 USD ($) agreement
Line of Credit Facility [Line Items]
Number of facility agreements \| agreement			2
Repayments of principal		$ 64.4	$ 25.4
Corporate credit cards
Line of Credit Facility [Line Items]
Maximum borrowing capacity		23.6	18.6
Line of credit, outstanding		9.9	7.3
Aircraft fuel
Line of Credit Facility [Line Items]
Maximum borrowing capacity		46.5	38.0
Line of credit, outstanding		$ 8.0	$ 6.9
Airbus
Line of Credit Facility [Line Items]
Number of delivered aircraft with secured debt financing commitments \| aircraft		29
Airbus \| A320 \| Enhanced Equipment Trust Certificate
Line of Credit Facility [Line Items]
Number of delivered aircraft with secured debt financing commitments \| aircraft		3
Number of aircraft with secured debt financing commitments scheduled for delivery \| aircraft	3
Airbus \| A321 \| Enhanced Equipment Trust Certificate
Line of Credit Facility [Line Items]
Number of delivered aircraft with secured debt financing commitments \| aircraft		11
Number of aircraft with secured debt financing commitments scheduled for delivery \| aircraft	12
Aircraft and Related Flight Equipment
Line of Credit Facility [Line Items]
Face amount, commitment for future issuance		$ 144.5
Enhanced Equipment Trust Certificate
Line of Credit Facility [Line Items]
Long-term debt outstanding		$ 538.1
Enhanced Equipment Trust Certificate \| Equipment Notes, Series A
Line of Credit Facility [Line Items]
State interest rate percentage		4.10%
Enhanced Equipment Trust Certificate \| Equipment Notes, Series B
Line of Credit Facility [Line Items]
State interest rate percentage		4.45%
Enhanced Equipment Trust Certificate \| Aircraft and Related Flight Equipment
Line of Credit Facility [Line Items]
Number of trusts \| trust	2
Face amount, commitment for future issuance	$ 576.6	$ 38.5
Framework Agreement
Line of Credit Facility [Line Items]
Long-term debt outstanding		$ 379.0
Framework Agreement \| Senior loans
Line of Credit Facility [Line Items]
Debt instrument, term		12 years
Framework Agreement \| Junior loans
Line of Credit Facility [Line Items]
Debt instrument, term		7 years
Framework Agreement \| Airbus \| A320
Line of Credit Facility [Line Items]
Number of delivered aircraft with secured debt financing commitments \| aircraft		7
Framework Agreement \| Airbus \| A321
Line of Credit Facility [Line Items]
Number of delivered aircraft with secured debt financing commitments \| aircraft		3
Facility Agreement
Line of Credit Facility [Line Items]
Long-term debt outstanding		$ 185.0
Facility Agreement \| Senior loans
Line of Credit Facility [Line Items]
Debt instrument, term		12 years
Facility Agreement \| Junior loans
Line of Credit Facility [Line Items]
Debt instrument, term		7 years
Facility Agreement \| Airbus \| A320
Line of Credit Facility [Line Items]
Number of delivered aircraft with secured debt financing commitments \| aircraft		5
2016 Facility Agreement [Member]
Line of Credit Facility [Line Items]
Face amount, commitment for future issuance		$ 106.0
2016 Facility Agreement [Member] \| Senior loans
Line of Credit Facility [Line Items]
Debt instrument, term		10 years
2016 Facility Agreement [Member] \| Airbus \| A320
Line of Credit Facility [Line Items]
Number of aircraft with secured debt financing commitments scheduled for delivery \| aircraft		2
2016 Facility Agreement [Member] \| Airbus \| A321
Line of Credit Facility [Line Items]
Number of aircraft with secured debt financing commitments scheduled for delivery \| aircraft		1