FAIR VALUE DISCLOSURES - Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financial assets
Investment securities held-to-maturity	$ 85,823	$ 98,420
Other investments	138,767	102,971
Loans held for sale	10,700	29,500
Interest Receivable	35,884	29,500
Deposits
Noninterest-bearing	4,137,038	4,185,572
Savings	3,980,020	4,157,374
Time	1,242,412	1,330,263
Impaired Commercial And Commercial Real Estate Loans Member
Deposits
Principal Amount of Commercial and Commercial Real Estate Loans	4,600	28,800
Allowance for Loan and Lease Losses, Real Estate	2,500	9,700
Carrying value
Financial assets
Cash and short-term investments	534,531	434,842
Investment securities held-to-maturity	85,823	98,420
Other investments	138,767	102,971
Loans and leases	9,673,340	9,156,307
Interest Receivable	50,926	44,627
Deposits
Deposits	12,339,935	12,871,954
Short-term borrowings	1,161,047	296,203
Long-term debt	355,116	409,832
Interest Payable	6,567	4,498
Fair value
Financial assets
Cash and short-term investments	534,531	434,842
Investment securities held-to-maturity	78,924	99,898
Other investments	138,767	102,971
Loans and leases	9,290,399	9,172,111
Interest Receivable	50,926	44,627
Deposits
Deposits	12,309,592	12,869,567
Short-term borrowings	1,161,047	296,203
Long-term debt	356,370	411,569
Interest Payable	6,567	4,498
Fair Value, Inputs, Level 1 [Member] | Fair value
Financial assets
Cash and short-term investments	534,531	434,842
Investment securities held-to-maturity	0	0
Other investments	1,077	1,331
Loans and leases	0	0
Interest Receivable	0	0
Deposits
Deposits	0	0
Short-term borrowings	1,161,047	296,203
Long-term debt	0	0
Interest Payable	1,614	0
Fair Value, Inputs, Level 2 [Member] | Fair value
Financial assets
Cash and short-term investments	0	0
Investment securities held-to-maturity	78,924	99,898
Other investments	129,774	92,025
Loans and leases	0	0
Interest Receivable	15,042	15,170
Deposits
Deposits	12,309,592	12,869,567
Short-term borrowings	0	0
Long-term debt	356,370	411,569
Interest Payable	4,953	4,498
Fair Value, Inputs, Level 3 [Member] | Fair value
Financial assets
Cash and short-term investments	0	0
Investment securities held-to-maturity	0	0
Other investments	7,916	9,615
Loans and leases	9,290,399	9,172,111
Interest Receivable		29,457
Deposits
Deposits	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Interest Payable	$ 0	$ 0