Defined Contribution 401(k) Plan (Details) $ in Millions	2 Months Ended	12 Months Ended
	Feb. 28, 2018	Dec. 31, 2019 USD ($) defined_contribution_plan	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Defined Contribution Plan Disclosure [Line Items]
Defined contribution 401(k) plan, number of plans | defined_contribution_plan		3
Defined contribution 401(k) plan, requisite service period		60 days
Defined contribution 401(k) plan, requisite age		21 years
Defined contribution 401(k) plan, matching contributions made in period | $		$ 51.1	$ 36.7	$ 19.6
Pilots’ Retirement Savings Plan
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match	100.00%
Defined Contribution Plan, Employer Contribution, Percent Of Employees' Gross Pay, Initial Percentage		11.00%
Defined Contribution Plan, Employer Contribution, Percent Of Employees' Gross Pay, Annual Percentage Increase		1.00%
Defined Contribution Plan, Employer Contribution, Percent Of Employees' Gross Pay, Final Percentage		15.00%
Pilots’ Retirement Savings Plan | Maximum
Defined Contribution Plan Disclosure [Line Items]
Defined contribution 401(k) plan, maximum employer contribution percent of the employee’s annual compensation	9.00%