Segment Reporting (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) segment aircraft	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting
Number of operating segments | segment			3
Operating revenues	$ 831,936	$ 799,776	$ 2,407,110	$ 2,363,190
Operating expense	719,567	713,942	2,111,851	2,131,410
Depreciation and amortization expense	74,095	71,743	215,415	209,431
Interest expense	27,101	19,865	78,713	55,876
Segment profit (loss)	86,676	66,560	219,944	177,410
Identifiable intangible assets, other than goodwill	6,121	8,811	6,121	8,811	$ 8,249
Total assets	5,389,446	5,135,178	5,389,446	5,135,178	$ 5,007,966
Capital expenditures (including non-cash)	53,499	309,101	572,400	631,061
Segments
Segment Reporting
Segment profit (loss)	85,268	65,969	216,546	175,904
SkyWest Airlines
Segment Reporting
Operating revenues	578,109	502,600	1,598,812	1,473,003
Operating expense	491,115	436,504	1,387,125	1,278,730
Depreciation and amortization expense	34,049	34,942	98,396	103,858
Interest expense	5,276	6,584	16,811	19,997
Total assets	2,088,048	2,174,376	2,088,048	2,174,376
Capital expenditures (including non-cash)	27,118	15,385	85,895	37,270
SkyWest Airlines | Segments
Segment Reporting
Segment profit (loss)	81,718	59,512	194,876	174,276
ExpressJet Airlines Inc
Segment Reporting
Operating revenues	191,516	260,362	632,199	794,410
Operating expense	200,492	261,003	645,055	809,478
Depreciation and amortization expense	12,573	20,726	38,808	63,453
Interest expense	1,017	1,597	3,219	5,337
Identifiable intangible assets, other than goodwill	6,121	8,811	6,121	8,811
Total assets	721,939	1,268,096	721,939	1,268,096
Capital expenditures (including non-cash)	2,259	3,296	12,414	10,346
ExpressJet Airlines Inc | Segments
Segment Reporting
Segment profit (loss)	(9,993)	(2,238)	(16,075)	(20,405)
SkyWest Leasing
Segment Reporting
Operating revenues	62,311	36,814	176,099	95,777
Operating expense	27,960	16,435	79,671	43,202
Depreciation and amortization expense	27,473	16,075	78,211	42,120
Interest expense	20,808	11,684	58,683	30,542
Total assets	2,579,459	1,692,706	2,579,459	1,692,706
Capital expenditures (including non-cash)	24,122	290,420	$ 474,091	583,445
SkyWest Leasing | CRJ 200
Segment Reporting
Number of aircraft under contract | aircraft			4
SkyWest Leasing | Segments
Segment Reporting
Segment profit (loss)	$ 13,543	$ 8,695	$ 37,745	$ 22,033