Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 771,081	$ 855,796
Air traffic liability	411,286		$ 315,408
Refunds issued	$ 43,700
Minimum
Disaggregation of Revenue [Line Items]
Credit shell term expiration	60 days
Maximum
Disaggregation of Revenue [Line Items]
Credit shell term expiration	12 months
DOT—Domestic
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 697,828	753,100
DOT—Latin America
Disaggregation of Revenue [Line Items]
Total operating revenues	73,253	102,696
Passenger [Member]
Disaggregation of Revenue [Line Items]
Total operating revenues	753,550	838,065
Fare
Disaggregation of Revenue [Line Items]
Total operating revenues	321,447	416,345
Non-fare
Disaggregation of Revenue [Line Items]
Total operating revenues	432,103	421,720
Other
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 17,531	$ 17,731