Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2013

Accounting Policies [Abstract]

Depreciable lives used for the principal depreciable asset classifications

The depreciable lives used for the principal depreciable asset classifications are:

	Estimated Useful Life
Spare rotables and flight assemblies	Lesser of the useful life of equipment or average remaining fleet life
Other equipment and vehicles	5 to 7 years
Internal use software	3 to 10 years
Capital lease	Lease term

Components of depreciation and amortization expense

The following table illustrates the components of depreciation and amortization expense:

	Year Ended December 31,
	2013		2012		2011
	(in thousands)
Depreciation	$	8,340	$	6,156	$	5,186
Amortization of heavy maintenance	23,607		9,100		2,574
Total depreciation and amortization	$	31,947	$	15,256	$	7,760

Total cash proceeds received from the sale of mileage credit

The following table illustrates total cash proceeds received from the sale of mileage credits and the portion of such proceeds recognized in revenue immediately as marketing component:

	Cash proceeds from sale of miles to non-airline third parties		Portion of proceeds recognized immediately as marketing component
Year Ended	(in thousands)
December 31, 2013	$	28,496	$	23,124
December 31, 2012	24,938		20,998
December 31, 2011	20,954		16,580

Primary components of non-ticket revenue and the revenue recognition method utilized for each service or product

The following table summarizes the primary components of non-ticket revenue and the revenue recognition method utilized for each service or product:

		Year Ended December 31,
Non-ticket revenue	Recognition method	2013		2012		2011
		(in thousands)
Baggage	Time of departure	$	275,958	$	217,536	$	168,290
Passenger usage fee	Time of departure	188,911		149,577		71,757
Advance seat selection	Time of departure	59,241		48,956		42,112
Service charges for changes and cancellations	When itinerary is changed	32,546		27,762		25,927
Other		111,711		91,765		73,450
Non-ticket revenue		$	668,367	$	535,596	$	381,536

Aircraft maintenance expense

The table below summarizes the extent to which the Company’s maintenance costs are rate capped due to flight hour maintenance contracts:

	Year Ended December 31,
	2013		2012		2011
	(in thousands)
Flight hour-based maintenance expense	$	30,322	$	25,748	$	21,974
Non-flight hour-based maintenance expense	29,821		23,712		12,043
Total maintenance, materials and repairs	$	60,143	$	49,460	$	34,017