RELATED PARTY TRANSACTIONS (NARRATIVE) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Related Party Transaction Line Items
Accounts payable, current, total	$ 105,519		$ 105,519		$ 93,937
Sales Revenue Services Net	602,956	$ 592,453	1,836,636	$ 1,785,429
Affiliated Entity | Avion and Airmax [Member]
Related Party Transaction Line Items
Purchases from Related Party		$ 400	800
Accounts payable, current, total	$ 104		104
Affiliated Entity | Willis Towers Watson [Member]
Related Party Transaction Line Items
Purchases from Related Party			$ 2,800	$ 2,200
Chief Executive Officer | Avion and Airmax [Member]
Related Party Transaction Line Items
Equity Method Investment, Ownership Percentage	100.00%		100.00%