Flying Agreements Revenue and Lease, Airport Services and Other Revenues (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) aircraft	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Agreements with other airlines
Percentage of ASMs flown under fixed-fee arrangements			87.20%	88.00%
Percentage of ASMs flown under pro-rate arrangements			12.80%	12.00%
Rental income under operating leases
Operating lease revenue	$ 16,091	$ 15,928	$ 49,442	$ 48,933
Total operating revenues	766,171	789,443	2,183,645	2,323,680
Future minimum rental income
October 2023 through December 2023	11,405		11,405
2024	45,535		45,535
2025	40,565		40,565
2026	34,998		34,998
2027	34,977		34,977
Thereafter	86,296		86,296
Total future minimum rental income under operating leases	253,776		253,776
Deferred revenue recognized			111,900	25,800
Unbilled revenue recognized			8,700	14,400
Deferred revenue	315,900		315,900		$ 144,700
Deferred revenue in other current liabilities	10,000		10,000		5,200
Deferred revenue in other long-term liabilities	305,900		305,900		139,500
Unbilled revenue	11,200		11,200		19,900
Property and equipment and related assets	5,498,425		5,498,425		5,548,480
Gross receivables current	136,300		136,300
Gross receivables Non-current	200,000		200,000
Balance			37,385
Adjustments to credit loss reserves			(1,789)
Write-offs charged against allowance			(3,570)
Balance	32,026		32,026
Other Current Assets
Future minimum rental income
Unbilled revenue	3,400		3,400		9,900
Other Noncurrent Assets
Future minimum rental income
Unbilled revenue	7,800		7,800		$ 10,000
Other Noncurrent Liabilities
Future minimum rental income
Deferred lease revenue	59,300		$ 59,300
Aircraft in schedule service or under contract
Future minimum rental income
Number of aircraft | aircraft			493
United
Future minimum rental income
Number of aircraft | aircraft			198
United | United Express Prorate Agreement
Future minimum rental income
Agreement term			120 days
Delta
Future minimum rental income
Number of aircraft | aircraft			144
Delta | Delta Connection Prorate Agreement
Future minimum rental income
Agreement term			30 days
American
Future minimum rental income
Number of aircraft | aircraft			109
Jet aircraft and spare engines leased to third parties
Future minimum rental income
Property and equipment and related assets	206,100		$ 206,100
CRJ 200 | United | United Express Agreements
Future minimum rental income
Number of aircraft | aircraft			70
CRJ 200 | United | United Express Prorate Agreement
Future minimum rental income
Number of aircraft | aircraft			19
CRJ 200 | Delta | Delta Connection Prorate Agreement
Future minimum rental income
Number of aircraft | aircraft			15
CRJ 700 | United | United Express Agreements
Future minimum rental income
Number of aircraft | aircraft			19
CRJ 700 | Delta | Delta Connection Prorate Agreement
Future minimum rental income
Number of aircraft | aircraft			4
CRJ 700 | Delta | Delta Connection Agreements
Future minimum rental income
Number of aircraft | aircraft			5
CRJ 700 | American | American Capacity Purchase Agreement
Future minimum rental income
Number of aircraft | aircraft			89
CRJ 900 | Delta | Delta Connection Prorate Agreement
Future minimum rental income
Number of aircraft | aircraft			2
CRJ 900 | Delta | Delta Connection Agreements
Future minimum rental income
Number of aircraft | aircraft			35
E175
Future minimum rental income
Number of aircraft under purchase agreement | aircraft			23
E175 | Sky West Airlines Inc. | Alaska Capacity Purchase Agreement
Future minimum rental income
Number of aircraft | aircraft			42
E175 | United
Future minimum rental income
Number of aircraft under purchase agreement | aircraft			19
E175 | United | United Express Agreements
Future minimum rental income
Number of aircraft | aircraft			90
E175 | Delta
Future minimum rental income
Number of aircraft under purchase agreement | aircraft			3
E175 | Delta | Delta Connection Agreements
Future minimum rental income
Number of aircraft | aircraft			83
E175 | American | American Capacity Purchase Agreement
Future minimum rental income
Number of aircraft | aircraft			20
E175 | Alaska
Future minimum rental income
Number of aircraft under purchase agreement | aircraft			1
Flying agreements
Rental income under operating leases
Total operating revenues	741,898	763,514	$ 2,106,130	2,245,351
Flight operations revenue
Rental income under operating leases
Total operating revenues	511,929	534,781	1,479,987	1,589,128
Capacity purchase agreements fixed aircraft lease revenue
Rental income under operating leases
Total operating revenues	73,794	133,989	222,316	387,576
Capacity purchase agreements variable aircraft lease revenue
Rental income under operating leases
Total operating revenues	46,495		134,584
Prorate agreements revenue
Rental income under operating leases
Total operating revenues	109,680	94,744	269,243	268,647
Airport customer service and other revenue
Rental income under operating leases
Total operating revenues	8,182	10,001	28,073	29,396
Lease, airport services and other.
Rental income under operating leases
Total operating revenues	$ 24,273	$ 25,929	$ 77,515	$ 78,329