INCOME TAXES - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Allowance for credit losses and other contingent liabilities	$ 26,926	$ 28,175
Tax effect of other components of income on securities available-for-sale	34,745	38,140
Tax effect of other components of income on securities held-to-maturity	7,216	8,138
Operating lease liability	19,229	19,256
Other	2,603	2,074
Total deferred tax assets	90,719	95,783
Deferred tax liabilities:
Tax effect of other components of income on derivatives	2,368	5,394
Employee benefit plans	1,707	976
Tax effect of purchase accounting fair value adjustments	1,329	2,352
Difference in book and tax carrying value of fixed assets	2,230	4,261
Difference in book and tax basis of unearned loan fees	3,239	2,431
Operating lease asset	18,266	18,414
States taxes	2,166	2,801
Other	241	1,002
Total deferred tax liabilities	31,546	37,631
Net deferred tax asset (recorded in other assets)	$ 59,173	$ 58,152