Debt and Other Obligations (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Schedule of long-term debt instruments

Long-term debt is comprised of the following:

	As of				Twelve Months Ended December 31,
	2017		2016		2017		2016
	(in millions)				(weighted-average interest rates)
Fixed-rate senior term loans due through 2027	$	417.9	$	451.9	4.10	%	4.10	%
Fixed-rate junior term loans due through 2022	39.3		47.1		6.90	%	6.90	%
Fixed-rate loans due through 2029	518.0		—		3.83	%	N/A
Fixed-rate class A 2015-1 EETC due through 2028	408.6		409.8		4.10	%	4.10	%
Fixed-rate class B 2015-1 EETC due through 2024	92.0		103.6		4.45	%	4.45	%
Fixed-rate class AA 2017-1 EETC due through 2030	37.5		—		3.38	%	N/A
Fixed-rate class A 2017-1 EETC due through 2030	12.5		—		3.65	%	N/A
Fixed-rate class B 2017-1 EETC due through 2026	13.8		—		3.80	%	N/A
Long-term debt	$	1,539.6	$	1,012.4
Less current maturities	115.4		84.4
Less unamortized discount, net	36.7		30.6
Total	$	1,387.5	$	897.4

Schedule of maturities of long-term debt

At December 31, 2017, long-term debt principal payments for the next five years and thereafter are as follows:

	December 31, 2017
	(in millions)
2018	$	121.0
2019	122.3
2020	121.8
2021	121.5
2022	118.8
2023 and beyond	934.2
Total debt principal payments	$	1,539.6

Schedule of interest expense on long-term debt

Interest expense related to long-term debt consists of the following:

	Twelve Months Ended December 31,
	2017		2016
	(in thousands)
Senior term loans	$	18,328	$	19,759
Junior term loans	3,035		3,568
Fixed-rate loans	8,610		—
Class A 2015-1 EETC	17,230		11,509
Class B 2015-1 EETC	4,446		3,243
Class AA 2017-1 EETC	54		—
Class A 2017-1 EETC	19		—
Class B 2017-1 EETC	22		—
Commitment fees	124		127
Amortization of deferred financing costs	5,280		3,435
Total	$	57,148	$	41,641