Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Segment Reporting
Operating revenues	$ 744,383	$ 805,515	$ 1,468,077	$ 1,588,915
Operating expense	600,290	678,837	1,227,565	1,374,062
Depreciation and amortization expense	90,148	82,714	180,134	160,298
Special items			21,869
Interest expense	32,770	28,811	65,278	55,045
Segment profit (loss)	115,335	98,327	229,778	165,530
Identifiable intangible assets, other than goodwill		2,448		2,448
Total assets	6,580,019	5,913,093	6,580,019	5,913,093	$ 6,313,212
Capital expenditures (including non-cash)	135,662	364,717	550,241	632,505
Segments
Segment Reporting
Segment profit (loss)	111,323	97,867	175,234	159,808
SkyWest Airlines
Segment Reporting
Operating revenues	627,088	587,480	1,212,856	1,143,775
Operating expense	545,419	494,143	1,091,320	993,019
Depreciation and amortization expense	40,641	38,841	80,694	76,327
Special items			18,508
Interest expense	3,716	4,202	7,534	8,678
Total assets	2,738,868	2,222,784	2,738,868	2,222,784
Capital expenditures (including non-cash)	47,975	40,039	116,625	76,322
SkyWest Airlines | Segments
Segment Reporting
Segment profit (loss)	77,953	89,135	114,002	142,078
ExpressJet Airlines Inc
Segment Reporting
Operating revenues		143,707	24,050	304,788
Operating expense		148,525	28,690	315,349
Depreciation and amortization expense		10,200	971	21,362
Special items			3,361
Interest expense		788		1,615
Identifiable intangible assets, other than goodwill		2,448		2,448
Total assets		563,198		563,198
Capital expenditures (including non-cash)		1,588		2,926
ExpressJet Airlines Inc | Segments
Segment Reporting
Segment profit (loss)		(5,606)	(4,640)	(12,176)
SkyWest Leasing
Segment Reporting
Operating revenues	117,295	74,328	231,171	140,352
Operating expense	54,871	36,169	107,555	65,694
Depreciation and amortization expense	49,507	33,673	98,469	62,609
Interest expense	29,054	23,821	57,744	44,752
Total assets	3,841,151	3,127,111	3,841,151	3,127,111
Capital expenditures (including non-cash)	87,687	323,090	433,616	553,257
SkyWest Leasing | Segments
Segment Reporting
Segment profit (loss)	$ 33,370	$ 14,338	$ 65,872	$ 29,906