Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Long-term debt measured at fair value

The carrying amounts and estimated fair values of the Company's long-term debt at December 31, 2019 and December 31, 2018, were as follows:

	As of December 31,
	2019				2018
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value		Fair value level hierarchy
	(in millions)
Fixed-rate senior term loans	$	296.1	$	296.4	$	382.4	$	373.6	Level 3
Fixed-rate junior term loans	—		—		31.1		31.1		Level 3
Fixed-rate term loans	778.2		823.6		625.1		600.1		Level 3
2015-1 EETC Class A	348.6		372.2		378.6		374.8		Level 2
2015-1 EETC Class B	72.0		74.5		80.0		78.1		Level 2
2015-1 EETC Class C	98.1		100.5		109.5		107.9		Level 2
2017-1 EETC Class AA	228.4		237.0		242.5		228.8		Level 2
2017-1 EETC Class A	76.1		78.8		80.8		76.6		Level 2
2017-1 EETC Class B	70.6		72.0		83.7		79.1		Level 2
2017-1 EETC Class C	85.5		88.0		85.5		84.2		Level 2
Revolving credit facility	160.0		160.0		135.3		135.3		Level 3
Total long-term debt	$	2,213.6	$	2,303.0	$	2,234.5	$	2,169.6

Assets and liabilities measured at fair value on a recurring basis

Assets and liabilities measured at gross fair value on a recurring basis are summarized below:

	Fair Value Measurements as of December 31, 2019
	Total		Level 1		Level 2		Level 3
	(in millions)
Cash and cash equivalents	$	979.0	$	979.0	$	—	$	—
Short-term investment securities	105.3		105.3		—		—
Assets held for sale	2.3		—		—		2.3
Total assets	$	1,086.6	$	1,084.3	$	—	$	2.3
Total liabilities	$	—	$	—	$	—	$	—

	Fair Value Measurements as of December 31, 2018
	Total		Level 1		Level 2		Level 3
	(in millions)
Cash and cash equivalents	$	1,004.7	$	1,004.7	$	—	$	—
Short-term investment securities	102.8		102.8		—		—
Total assets	$	1,107.5	$	1,107.5	$	—	$	—
Total liabilities	$	—	$	—	$	—	$	—

The following table presents the Company's activity for assets and liabilities measured at gross fair value on a recurring basis using significant unobservable inputs (Level 3):

	Assets Held for Sale Activity for the Twelve Months Ended December 31, 2019
	(in millions)
Balance at December 31, 2018	$	—
Purchases	5.4
Sales	—
Total realized or unrealized gains (losses) included in earnings, net	(3.1		)
Balance at December 31, 2019	$	2.3