Revenue Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Air traffic liability	$ 403,001		$ 291,981
Total operating revenues	855,796	$ 704,138
DOT—Domestic [Member]
Disaggregation of Revenue [Line Items]
Total operating revenues	753,100	647,807
DOT—Latin America [Member]
Disaggregation of Revenue [Line Items]
Total operating revenues	102,696	56,331
Passenger [Member]
Disaggregation of Revenue [Line Items]
Total operating revenues	838,065	689,141
Fare [Member]
Disaggregation of Revenue [Line Items]
Total operating revenues	416,345	342,695
Non Fare [Member]
Disaggregation of Revenue [Line Items]
Total operating revenues	421,720	346,446
Other [Member]
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 17,731	$ 14,997