GOODWILL, OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS (Finite-Lived Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Line Items]
Goodwill, beginning of period	$ 373,121	$ 373,121	$ 373,121
Goodwill, end of period	373,121	373,121	373,121
Intangible Assets, Net (Including Goodwill), beginning of period	382,561	387,976	394,547
Intangible Assets, Net (Including Goodwill), end of period	378,805	382,561	387,976
Amortization	(3,756)	(5,279)	(6,571)
Finite-Lived Intangible Assets, Other Changes		(136)
Core Deposit Intangibles [Member]
Goodwill [Line Items]
Balance, beginning of period	9,440	14,855	21,426
Amortization	(3,756)	(5,279)	(6,571)
Finite-Lived Intangible Assets, Other Changes		(136)
Balance, end of period	$ 5,684	$ 9,440	$ 14,855