Nature of Operations and Summary of Significant Accounting Policies (Details 8) - aircraft	12 Months Ended	18 Months Ended
	Dec. 31, 2015	Jun. 30, 2017
Delta Connection Agreements | Forecast
Agreements with other airlines
Number of aircraft under contract		19
Delta Connection Agreements | ExpressJet
Agreements with other airlines
Term of agreement	3 years 8 months 12 days
Delta Connection Agreements | Sky West Airlines Inc
Agreements with other airlines
Term of agreement	3 years 9 months 18 days
Delta Connection Agreements | CRJ 200 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	42
Delta Connection Agreements | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	48
Delta Connection Agreements | CRJ 700 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	41
Delta Connection Agreements | CRJ 700 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	19
Delta Connection Agreements | CRJ 900 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	28
Delta Connection Agreements | CRJ 900 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	36
United Express Agreements | Forecast
Agreements with other airlines
Number of aircraft under contract		25
United Express Agreements | ExpressJet
Agreements with other airlines
Term of agreement	1 year 10 months 24 days
United Express Agreements | Sky West Airlines Inc
Agreements with other airlines
Term of agreement	4 years 3 months 18 days
United Express Agreements | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	57
United Express Agreements | CRJ 700 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	70
United Express Agreements | E 175 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	40
United Express Agreements | ERJ135 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	5
United Express Agreements | ERJ 145 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	166
United Express Prorate Agreement | Sky West Airlines Inc
Agreements with other airlines
Notice period for termination of agreement	120 days
United Express Prorate Agreement | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	26
Alaska Capacity Purchase Agreement | Forecast
Agreements with other airlines
Number of aircraft under contract		10
Alaska Capacity Purchase Agreement | CRJ 700 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	9
Alaska Capacity Purchase Agreement | E 175 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	5
American Capacity Purchase Agreement | CRJ 200 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	11
American Capacity Purchase Agreement | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	12
American Capacity Purchase Agreement | ERJ 145 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	16
American Capacity Prorate Agreement | Sky West Airlines Inc
Agreements with other airlines
Notice period for termination of agreement	120 days
American Capacity Prorate Agreement | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	5
Prorate Agreement | ExpressJet
Agreements with other airlines
Notice period for termination of agreement	120 days
Prorate Agreement | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	21
Notice period for termination of agreement	30 days
Prorate Agreement | CRJ 200 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	3