| Cover | Oct. 29, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 29, 2020 |
| Entity File Number | 0-14719 |
| Entity Registrant Name | SKYWEST, INC. |
| Entity Central Index Key | 0000793733 |
| Entity Tax Identification Number | 87-0292166 |
| Entity Incorporation, State or Country Code | UT |
| Entity Address, Address Line One | 444 South River Road |
| Entity Address, City or Town | St. George |
| Entity Address, State or Province | UT |
| Entity Address, Postal Zip Code | 84790 |
| City Area Code | 435 |
| Local Phone Number | 634-3000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, No Par Value |
| Trading Symbol | SKYW |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
