Represents the maximum percentage of the participant's compensation eligible for the employer matching contribution.

No definition available.

Name:	skyw_DefinedBenefitPlanMaximumPercentageOfParticipantTotalCompensationEligibleForEmployerMatchingContribution
Namespace Prefix:	skyw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the maximum percentage of the employer's matching contribution for participant contributions based upon the length of service.

+ References

No definition available.

+ Details

Name:	skyw_DefinedBenefitPlanPercentageOfEmployerMatchingContributionForParticipantContributionsBasedUponLengthOfService
Namespace Prefix:	skyw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the age required to be completed by the employee to be eligible to participate in the plan.

+ References

No definition available.

+ Details

Name:	skyw_DefinedBenefitPlanRequiredAge
Namespace Prefix:	skyw_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the estimated period of time over which an employee is required to provide service to participate in the defined benefit plan.

+ References

No definition available.

+ Details

Name:	skyw_DefinedBenefitPlanRequisiteServicePeriod
Namespace Prefix:	skyw_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of vesting for plan participants in their elective deferrals and rollover amounts.

+ References

No definition available.

+ Details

Name:	skyw_DefinedBenefitPlanVestingPercentageForElectiveDeferralsAndRolloverAmounts
Namespace Prefix:	skyw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the maximum benefit plan percentage of participants compensation eligible for employer matching contribution based on position and years of service.

+ References

No definition available.

+ Details

Name:	skyw_MaximumBenefitPlanPercentageOfParticipantsCompensationEligibleForEmployerMatchingContributionBasedOnPositionAndYearsOfService
Namespace Prefix:	skyw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the minimum benefit plan percentage of participants compensation eligible for employer matching contribution based on position and years of service.

+ References

No definition available.

+ Details

Name:	skyw_MinimumBenefitPlanPercentageOfParticipantsCompensationEligibleForEmployerMatchingContributionBasedOnPositionAndYearsOfService
Namespace Prefix:	skyw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=112275985&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(iv)(01)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(ii)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e2709-114920

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

Name:	us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RetirementPlanNameAxis=skyw_SkyWestIncEmployeesRetirementPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanNameAxis=skyw_AtlanticSoutheastAndExpressJetRetirementPlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanNameAxis=skyw_AtlanticSoutheastAirlinesIncInvestmentSavingsPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Retirement Plans and Employee Stock Purchase Plans - Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SkyWest Plan
Retirement Plans
Service period required to be completed to be eligible to participate in plan	90 days
Required age for an employee to be eligible to participate in plan	18 years
Percentage of employer matching contribution based on length of service	100.00%
Minimum benefit plan percentage of participants compensation eligible for employer matching contribution based on position and years of service	2.00%
Maximum benefit plan percentage of participants compensation eligible for employer matching contribution based on position and years of service	12.00%
Company's combined contributions	$ 35.6	$ 26.1	$ 23.2
Atlantic Southeast and the ExpressJet Plans
Retirement Plans
Service period required to be completed to be eligible to participate in plan	90 days
Required age for an employee to be eligible to participate in plan	18 years
Company's combined contributions	$ 15.4	$ 17.8	$ 21.0
Maximum percentage of participant's total compensation eligible for employer matching contribution	6.00%
Atlantic Southeast Plan
Retirement Plans
Percentage of vesting for plan participants' elective deferrals and rollover amounts	100.00%