Special Items (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($) aircraft	Dec. 31, 2017 aircraft	Dec. 31, 2016 USD ($) item	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Total Special items			$ 465,649		$ 74,777
Aircraft rentals			262,602	$ 273,696	305,334
Proceeds from settlement of residual value guarantee aircraft agreements	$ 125,000		90,000
Paint facility
Total Special items					4,800
CRJ 200
Number of aircraft removed from service | aircraft	76
Total Special items			$ 424,466
Proceeds from settlement of residual value guarantee aircraft agreements	$ 125,000
CRJ 200 | Forecast
Number of aircraft removed from service | aircraft		46
EMB 120
Total Special items					57,046
ERJ 145
Number of extension rights | item			2
Term of extension rights			1 year
Total Special items			$ 41,183		12,931
Estimated fair value	$ 41,200		41,200		11,400
Aircraft rentals					1,500
ERJ 145 | Forecast
Number of aircraft removed from service | aircraft		45
SkyWest Airlines
Total Special items			184,295		57,046
Proceeds from settlement of residual value guarantee aircraft agreements			90,000
ExpressJet Airlines Inc
Total Special items			281,354		$ 17,731
ExpressJet Airlines Inc | CRJ 200
Total Special items			$ 240,200