Segment Reporting (Details) $ in Thousands		3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) aircraft	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) segment	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting
Number of operating segments | segment				2
Operating revenues		$ 656,990	$ 350,039	$ 1,191,545	$ 1,079,975
Operating expense		541,967	354,442	995,680	1,018,057
Depreciation and amortization expense		109,895	131,638	219,492	243,346
Interest expense		33,940	30,926	65,294	61,130
Segment profit (loss)		81,083	(35,329)	130,571	788
Total assets (as of June 30)	$ 6,991,763	6,991,763	6,773,383	6,991,763	6,773,383	$ 6,887,622
Capital expenditures (including non-cash)		26,439	72,260	83,947	183,384
Number of aircraft | aircraft	478
SkyWest Airlines
Segment Reporting
Operating revenues		527,595	227,808	934,045	834,650
Operating expense		477,188	275,869	865,058	870,010
Depreciation and amortization expense		53,151	59,421	103,477	111,197
Interest expense		6,219	3,438	9,348	5,979
Segment profit (loss)		44,188	(51,499)	59,639	(41,339)
Total assets (as of June 30)	$ 3,089,404	3,089,404	2,789,321	3,089,404	2,789,321
Capital expenditures (including non-cash)		21,822	29,247	57,028	68,126
SkyWest Leasing
Segment Reporting
Operating revenues		129,395	122,231	257,500	245,325
Operating expense		64,779	78,573	130,622	148,047
Depreciation and amortization expense		56,744	72,217	116,015	132,149
Interest expense		27,721	27,488	55,946	55,151
Segment profit (loss)		36,895	16,170	70,932	42,127
Total assets (as of June 30)	$ 3,902,359	3,902,359	3,984,062	3,902,359	3,984,062
Capital expenditures (including non-cash)		$ 4,617	$ 43,013	$ 26,919	$ 115,258