Defined Contribution 401(k) Plan (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			0 Months Ended	5 Months Ended	7 Months Ended
	Dec. 31, 2014 defined_contribution_plan	Dec. 31, 2013	Dec. 31, 2012	Feb. 01, 1994	Dec. 31, 2014	Jul. 31, 2014
Defined Contribution Plan Disclosure [Line Items]
Defined contribution 401(k) plan, number of plans	3				3
Defined contribution 401(k) plan, matching contributions made in period	$ 9.7	$ 7.7	$ 6.6
Employee Retirement Savings Plan
Defined Contribution Plan Disclosure [Line Items]
Defined contribution 401(k) plan, requisite service period	60 days			1 year
Defined contribution 401(k) plan, requisite service period, hours				1000 hours
Defined contribution 401(k) plan, requisite age				21 years
Defined contribution plan, employer matching contribution, percent of match	50.00%
Employee 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	3.00%
Pilots’ Retirement Savings Plan
Defined Contribution Plan Disclosure [Line Items]
Defined contribution 401(k) plan, requisite service period	60 days
Defined contribution 401(k) plan, requisite age	21 years
Defined contribution plan, employer matching contribution, percent of match					100.00%	100.00%
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%	8.00%
Puerto Rico Retirement Savings Plan | Pilots
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match					100.00%	100.00%
Puerto Rico Retirement Savings Plan | Other Employees
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match	50.00%
Puerto Rico Retirement Savings Plan | Maximum | Pilots
Defined Contribution Plan Disclosure [Line Items]
Defined contribution 401(k) plan, maximum employer contribution percent of the employee’s annual compensation					9.00%	8.00%
Puerto Rico Retirement Savings Plan | Maximum | Other Employees
Defined Contribution Plan Disclosure [Line Items]
Defined contribution 401(k) plan, maximum employer contribution percent of the employee’s annual compensation	3.00%