DEBT - Long-term debt (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2019 USD ($) aircraft	Dec. 31, 2025 USD ($) aircraft	Dec. 31, 2024 USD ($) aircraft	Dec. 31, 2023 USD ($) aircraft	Mar. 31, 2022 USD ($) aircraft
DEBT
Number of aircrafts | aircraft		70	63	60
Repayment of long-term debt		$ 111,711	$ 145,518	$ 69,276
Other | Owned Aircraft Held for Operating Lease
DEBT
Number of aircrafts | aircraft		2	4	5
B-737-900
DEBT
Number of aircrafts | aircraft				5
Term Loan
DEBT
Face amount		$ 108,000
Repayment of long-term debt		$ 20,953
Debt instrument, interest rate, effective percentage		5.98%
Margin (as a percent)		2.60%
Payments of debt issuance costs		$ 1,604
Gain (loss) on extinguishment of debt		$ (391)
Term Loan | Notes Payable, Other Payables
DEBT
Face amount				$ 119,200
2022-1 EETC (see terms and conditions above) | Notes Payable, Other Payables
DEBT
Face amount					$ 188,277
Number of aircraft financed by debt issuance | aircraft					13
Weighted average interest rate		5.04%
2022-1 EETC (see terms and conditions above) | Notes Payable, Other Payables | Maximum
DEBT
Interest rate					5.75%
2022-1 EETC (see terms and conditions above) | Notes Payable, Other Payables | Minimum
DEBT
Interest rate					4.84%
Notes payable under the Company's 2019-1 EETC agreement
DEBT
Face amount	$ 248,587
Weighted average interest rate		5.56%
Number of used aircrafts purchased or refinanced | aircraft	13
Notes payable under the Company's 2019-1 EETC agreement | Maximum
DEBT
Interest rate	7.10%
Notes payable under the Company's 2019-1 EETC agreement | Minimum
DEBT
Interest rate	4.13%
Notes payable under the Company's 2019-1 EETC agreement | Notes Payable, Other Payables
DEBT
Face amount		$ 60,000		$ 60,000