Segment Reporting (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) segment	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting
Number of operating segments | segment			3
Operating revenues	$ 457,493	$ 760,295	$ 1,537,469	$ 2,228,372
Operating expense	382,940	613,854	1,400,998	1,841,419
Depreciation and amortization expense	121,467	92,795	364,813	272,929
Special items				21,869
Interest expense	30,150	31,606	91,280	96,884
Segment profit (loss)	46,211	118,738	52,048	348,517
Total assets	6,758,594	6,597,659	6,758,594	6,597,659	$ 6,657,129
Capital expenditures (including non-cash)	4,937	101,991	188,321	652,232
Segments
Segment Reporting
Segment profit (loss)	44,403	114,835	45,191	290,069
SkyWest Airlines
Segment Reporting
Operating revenues	337,975	641,947	1,172,625	1,854,803
Operating expense	303,141	560,646	1,173,152	1,651,966
Depreciation and amortization expense	59,659	43,353	170,855	124,048
Special items				18,508
Interest expense	2,868	3,165	8,847	10,699
Total assets	2,836,069	2,744,191	2,836,069	2,744,191
Capital expenditures (including non-cash)	4,937	67,394	73,063	184,019
SkyWest Airlines | Segments
Segment Reporting
Segment profit (loss)	31,966	78,136	(9,374)	192,138
ExpressJet Airlines Inc
Segment Reporting
Operating revenues				24,050
Operating expense				28,690
Depreciation and amortization expense				971
Special items				3,361
ExpressJet Airlines Inc | Segments
Segment Reporting
Segment profit (loss)				(4,640)
SkyWest Leasing
Segment Reporting
Operating revenues	119,518	118,348	364,844	349,519
Operating expense	79,799	53,208	227,846	160,763
Depreciation and amortization expense	61,808	49,442	193,958	147,910
Interest expense	27,282	28,441	82,433	86,185
Total assets	3,922,525	3,853,468	3,922,525	3,853,468
Capital expenditures (including non-cash)		34,597	115,258	468,213
SkyWest Leasing | Segments
Segment Reporting
Segment profit (loss)	$ 12,437	$ 36,699	$ 54,565	$ 102,571