Summary of Significant Accounting Policies - Maintenance Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Amortization of heavy maintenance	$ 43,111	$ 35,802	$ 23,607
Deferred costs for heavy maintenance	9,100	33,600	70,800
Deferred heavy maintenance, gross	208,100	198,900
Accumulated heavy maintenance amortization	65,524	36,099
Airframe and Engine Maintenance Costs [Abstract]
Flight hour-based maintenance expense	41,818	35,675	30,322
Non-flight hour-based maintenance expense	38,630	38,281	29,821
Total maintenance, materials and repairs	80,448	73,956	$ 60,143
Heavy Maintenance
Property, Plant and Equipment [Line Items]
Accumulated heavy maintenance amortization	$ 118,900	$ 75,800