Segment Reporting (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) segment	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting
Number of operating segments | segment			2
Operating revenues	$ 744,783	$ 457,493	$ 1,936,328	$ 1,537,469
Operating expense	697,733	382,940	1,693,413	1,400,998
Depreciation and amortization expense	109,597	121,467	329,089	364,813
Special items - impairment charges	84,592		84,592
Interest expense	28,980	30,150	94,274	91,280
Segment profit (loss)	18,070	44,403	148,641	45,191
Total assets (as of September 30)	6,940,502	6,758,594	6,940,502	6,758,594	$ 6,887,622
Capital expenditures (including non-cash)	163,299	4,937	247,246	188,321
SkyWest Airlines
Segment Reporting
Operating revenues	614,377	337,975	1,548,422	1,172,625
Operating expense	633,169	303,141	1,498,227	1,173,152
Depreciation and amortization expense	53,401	59,659	156,878	170,855
Special items - impairment charges	84,592		84,592
Interest expense	2,138	2,868	11,486	8,847
Segment profit (loss)	(20,930)	31,966	38,709	(9,374)
Total assets (as of September 30)	2,989,600	2,836,069	2,989,600	2,836,069
Capital expenditures (including non-cash)	26,622	4,937	83,650	73,063
SkyWest Leasing
Segment Reporting
Operating revenues	130,406	119,518	387,906	364,844
Operating expense	64,564	79,799	195,186	227,846
Depreciation and amortization expense	56,196	61,808	172,211	193,958
Interest expense	26,842	27,282	82,788	82,433
Segment profit (loss)	39,000	12,437	109,932	54,565
Total assets (as of September 30)	3,950,902	$ 3,922,525	3,950,902	3,922,525
Capital expenditures (including non-cash)	$ 136,677		$ 163,596	$ 115,258