Retirement Plans and Employee Stock Purchase Plans (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		12 Months Ended
	Dec. 31, 2007	Nov. 30, 2007	Dec. 31, 2013	Dec. 31, 2013 Minimum	Dec. 31, 2013 Maximum	Dec. 31, 2013 SkyWest Plan	Dec. 31, 2012 SkyWest Plan	Dec. 31, 2011 SkyWest Plan	Dec. 31, 2013 Atlantic Southeast and the ExpressJet Plans	Dec. 31, 2012 Atlantic Southeast and the ExpressJet Plans	Dec. 31, 2011 Atlantic Southeast and the ExpressJet Plans	Dec. 31, 2013 Atlantic Southeast Plan	Dec. 31, 2013 Atlantic Southeast Plan Minimum	Dec. 31, 2013 Atlantic Southeast Plan Maximum
Retirement Plans
Service period required to be completed to be eligible to participate in plan						90 days						90 days
Required age for an employee to be eligible to participate in plan						18 years						18 years
Percentage of employer matching contribution based on length of service						100.00%							20.00%	75.00%
Percentage of participant's compensation eligible for employer's matching contribution based upon length of service, threshold one						2.00%
Percentage of participant's compensation eligible for employer's matching contribution based upon length of service, threshold two						4.00%
Percentage of participant compensation eligible for employer's matching contribution based upon length of service, threshold three						6.00%
Company's combined contributions						$ 18.3	$ 16.0	$ 14.4	$ 26.7	$ 26.4	$ 25.1
Maximum percentage of participant's total compensation eligible for employer matching contribution												6.00%
Minimum service period required to be completed for eight percent matching contribution by the employer												10 years
Maximum percentage of participant's total compensation eligible for employer matching contribution after requisite service period												8.00%
Percentage of vesting for plan participants' elective deferrals and rollover amounts												100.00%
Percentage of vesting of company matching contribution based on length of service													10.00%	100.00%
ExpressJet Plan
Eligible age to provide medical bridge coverage				60 years	65 years
Minimum period of service required to be completed by retired employees for availing medical bridge coverage			10 years
Mandatory retirement age for commercial pilots	65 years	60 years