FAIR VALUE - Carrying Amounts and Estimated Fair Values of Other Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Carrying Value
Financial assets:
Net loans	$ 8,089,154	$ 7,323,770
Financial liabilities:
Deposits	13,357,772	12,911,168
Overnight Federal Reserve Bank borrowings	66,000	0
Securities sold under agreement to repurchase, short-term	223,755	324,720
Other Federal Home Loan Bank borrowings	19,471	1,888
Subordinated notes payable	3,263	3,277
Fair Value
Financial assets:
Net loans	8,073,820	7,523,024
Financial liabilities:
Deposits	13,333,288	12,911,197
Overnight Federal Reserve Bank borrowings	66,000	0
Securities sold under agreement to repurchase, short-term	223,755	324,720
Other Federal Home Loan Bank borrowings	19,655	1,907
Subordinated notes payable	$ 3,263	$ 3,277