Revenue Recognition - Disaggregation Of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Operating revenue	$ 559,144	$ 656,751
Passenger revenue, excluding frequent flyer
Disaggregation of Revenue [Line Items]
Operating revenue	474,135	567,855
Frequent flyer revenue, transportation component
Disaggregation of Revenue [Line Items]
Operating revenue	29,334	33,449
Passenger Revenue
Disaggregation of Revenue [Line Items]
Operating revenue	503,469	601,304
Other revenue (e.g., cargo and other miscellaneous)
Disaggregation of Revenue [Line Items]
Operating revenue	34,183	36,231
Frequent flyer revenue, marketing and brand component
Disaggregation of Revenue [Line Items]
Operating revenue	21,492	19,216
Other Revenue
Disaggregation of Revenue [Line Items]
Operating revenue	55,675	55,447
Domestic
Disaggregation of Revenue [Line Items]
Operating revenue	402,014	477,520
Pacific
Disaggregation of Revenue [Line Items]
Operating revenue	$ 157,130	$ 179,231