v3.26.3
Segments - Schedule of Segment Reporting Information, by Segment (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Segment Reporting [Line Items]          
Passenger $ 777,448 $ 494,144 $ 2,271,739 $ 1,728,802  
Third party products 44,616 39,397 132,709 108,249  
Fixed fee contracts 83,646 18,852 147,491 52,123  
Cargo 52,393 0 79,978 0  
Other 3,456 9,539 5,564 61,216  
Total operating revenues 961,559 561,932 2,637,481 1,950,390  
Salaries and benefits 287,387 196,394 755,790 641,935  
Aircraft fuel 293,575 151,254 781,485 483,339  
Station operations 113,986 71,390 286,020 220,143  
Depreciation and amortization 81,172 58,952 209,806 190,782  
Maintenance and repairs 59,784 39,908 144,253 111,141  
Sales and marketing 35,810 23,040 99,205 74,973  
Aircraft rent 7,739 11,096 22,215 28,038  
Other 52,267 33,615 112,916 109,873  
Special charges, net of recoveries 19,084 3,473 112,818 119,842  
Total operating expenses 950,804 589,122 2,524,508 1,980,066  
OPERATING INCOME (LOSS) 10,755 (27,190) 112,973 (29,676)  
Interest income (9,673) (10,108) (27,226) 32,402  
Interest expense 46,555 38,116 115,856 114,656  
Capitalized interest (6,189) (3,166) (15,417) (14,216)  
Other non-operating expense 112 122 (994) 1,064  
INCOME (LOSS) BEFORE INCOME TAXES (20,050) (52,154) 40,754 (98,778)  
Segment Reporting, Long-Lived Asset, Expenditure for Addition 135,680 129,278 499,750 351,573  
Assets 6,346,981   6,346,981   $ 4,209,401
Scheduled Service | Operating Segments          
Segment Reporting [Line Items]          
Passenger 387,182 177,194 1,136,942 707,771  
Ancillary Air-related Charges | Operating Segments          
Segment Reporting [Line Items]          
Passenger 372,776 295,548 1,075,965 963,700  
Loyalty Redemptions | Operating Segments          
Segment Reporting [Line Items]          
Passenger 17,490 21,402 58,832 57,331  
Allegiant Air          
Segment Reporting [Line Items]          
Third party products 42,292 39,397 129,110 108,249  
Fixed fee contracts 20,627 18,852 53,273 52,123  
Cargo 0   0    
Other 174 181 533 536  
Total operating revenues 683,761 552,574 2,192,399 1,889,710  
Salaries and benefits 188,979 190,491 608,401 614,350  
Aircraft fuel 226,192 151,254 671,556 483,339  
Station operations 78,255 71,390 230,877 220,143  
Depreciation and amortization 57,561 58,952 174,008 183,623  
Maintenance and repairs 39,211 39,908 113,777 111,141  
Sales and marketing 27,632 22,093 85,693 70,583  
Aircraft rent 7,739 11,096 22,215 28,038  
Other 31,531 24,684 80,725 75,790  
Special charges, net of recoveries 11,792 2,907 79,089 18,894  
Total operating expenses 668,892 572,775 2,066,341 1,805,901  
OPERATING INCOME (LOSS) 14,869 (20,201) 126,058 83,809  
Interest income (8,472) (10,108) (25,279) 32,402  
Interest expense 38,418 34,120 102,847 91,190  
Capitalized interest (6,189) (3,166) (15,417) (14,216)  
Other non-operating expense 42 122 (1,028) 1,064  
INCOME (LOSS) BEFORE INCOME TAXES (8,930) (41,169) 64,935 38,173  
Segment Reporting, Long-Lived Asset, Expenditure for Addition 131,899 129,278 491,082 350,131  
Assets 4,457,903   4,457,903   4,209,401
Allegiant Air | Scheduled Service | Operating Segments          
Segment Reporting [Line Items]          
Passenger 292,087 177,194 978,239 707,771  
Allegiant Air | Ancillary Air-related Charges | Operating Segments          
Segment Reporting [Line Items]          
Passenger 312,230 295,548 974,245 963,700  
Allegiant Air | Loyalty Redemptions | Operating Segments          
Segment Reporting [Line Items]          
Passenger 16,351 21,402 56,999 57,331  
Sun Country Airlines          
Segment Reporting [Line Items]          
Third party products 2,324        
Fixed fee contracts 63,019        
Cargo 52,393        
Other 3,282        
Total operating revenues 277,798        
Salaries and benefits 98,408        
Aircraft fuel 67,383        
Station operations 35,731        
Depreciation and amortization 23,611        
Maintenance and repairs 20,573        
Sales and marketing 8,178        
Aircraft rent 0        
Other 20,736        
Special charges, net of recoveries 7,292        
Total operating expenses 281,912        
OPERATING INCOME (LOSS) (4,114)        
Interest income (1,201)        
Interest expense 8,137        
Capitalized interest 0        
Other non-operating expense 70        
INCOME (LOSS) BEFORE INCOME TAXES (11,120)        
Segment Reporting, Long-Lived Asset, Expenditure for Addition 3,781        
Assets 1,889,078   1,889,078   $ 0
Sun Country Airlines | Scheduled Service | Operating Segments          
Segment Reporting [Line Items]          
Passenger 95,095 0 158,703 0  
Sun Country Airlines | Ancillary Air-related Charges | Operating Segments          
Segment Reporting [Line Items]          
Passenger 60,546 0 101,720 0  
Sun Country Airlines | Loyalty Redemptions | Operating Segments          
Segment Reporting [Line Items]          
Passenger $ 1,139 0 1,833 0  
Sunseeker          
Segment Reporting [Line Items]          
Third party products   0 3,599 0  
Fixed fee contracts   0 94,218 0  
Cargo     79,978    
Other   9,358 5,031 60,680  
Total operating revenues   9,358 445,082 60,680  
Salaries and benefits   5,903 147,389 27,585  
Aircraft fuel   0 109,929 0  
Station operations   0 55,143 0  
Depreciation and amortization   0 35,798 7,159  
Maintenance and repairs   0 30,476 0  
Sales and marketing   947 13,512 4,390  
Aircraft rent   0 0 0  
Other   8,931 32,191 34,083  
Special charges, net of recoveries   566 33,729 100,948  
Total operating expenses   16,347 458,167 174,165  
OPERATING INCOME (LOSS)   (6,989) (13,085) (113,485)  
Interest income   0 (1,947) 0  
Interest expense   3,996 13,009 23,466  
Capitalized interest   0 0 0  
Other non-operating expense   0 34 0  
INCOME (LOSS) BEFORE INCOME TAXES   (10,985) (24,181) (136,951)  
Segment Reporting, Long-Lived Asset, Expenditure for Addition   $ 0 $ 8,668 $ 1,442