GOODWILL AND OTHER INTANGIBLE ASSETS - Changes in Carrying Amount of Goodwill and Intangibles (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Roll Forward]
Balance, beginning	$ 223,642	$ 497,260	$ 223,642	$ 223,642
Amortization			273,618
Balance, ending		497,318	497,260	223,642
Finite-Lived Intangible Assets [Roll Forward]
Balance, beginning		143,525
Amortization		(26,883)	(9,303)	(3,296)
Goodwill true-up	58	58
Balance, ending		116,712	143,525
Core Deposit Intangibles
Finite-Lived Intangible Assets [Roll Forward]
Balance, beginning	14,658	143,525	14,658	17,954
Acquired intangibles			138,150
Amortization		(26,813)	(9,283)	(3,296)
Balance, ending		116,712	143,525	14,658
Servicing Assets
Finite-Lived Intangible Assets [Roll Forward]
Balance, beginning	$ 0	309	0	0
Acquired intangibles			329
Amortization		(70)	(20)	0
Decrease due to payoff of serviced loans		(27)
Balance, ending		$ 212	$ 309	$ 0