Number of persons employed by the Entity

No definition available.

Name:	dei_EntityNumberOfEmployees
Namespace Prefix:	dei_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents a commitment to purchase specified number of aircraft.

+ References

No definition available.

+ Details

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Namespace Prefix:	skyw_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the approximate number of active employees in employee groups.

+ References

No definition available.

+ Details

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Namespace Prefix:	skyw_
Data Type:	xbrli:integerItemType
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

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of obligations and payables pertaining to claims incurred of a workers compensation nature. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Details

Name:	srt_AircraftTypeAxis=skyw_E175Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=srt_CRJ700Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_RevenueFromRightsConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=skyw_DeltaUnitedContinentalCombinedMember
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Data Type:	na
Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_LaborForceConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=skyw_SkyWestAirlinesMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_UnionizedEmployeesConcentrationRiskMember
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Commitments and Contingencies (Details) $ in Millions	3 Months Ended	12 Months Ended
Commitments and Contingencies (Details) $ in Millions	Mar. 31, 2021 aircraft	Dec. 31, 2020 USD ($) employee aircraft	Dec. 31, 2019 USD ($)	Dec. 31, 2018
Concentration Risk and Significant Customers
Accrued workers' compensation liability \| $		$ 20.7	$ 23.9
E175
Concentration Risk and Significant Customers
Commitment to purchase number of aircraft \| aircraft		20
CRJ 700 \| Subsequent event
Concentration Risk and Significant Customers
Commitment to purchase number of aircraft \| aircraft	12
Revenue from rights, concentration risk \| Customer concentration risk \| Delta, United, and Continental Combined
Concentration Risk and Significant Customers
Concentration risk (as a percent)		76.40%	77.60%	81.40%
Full-time equivalent number of employees \| Labor force concentration risk
Concentration Risk and Significant Customers
Number of employees \| employee		12,502
SkyWest Airlines \| Full-time equivalent number of employees \| Unionized employees
Concentration Risk and Significant Customers
Approximate number of active employees \| employee		0