LOANS AND ALLOWANCE FOR CREDIT LOSSES - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Allowance for credit loss - loans
Beginning balance	$ 66,669
Charge-offs	(3,157)
Ending balance	79,114	$ 66,669
Accrued interest receivable on loans	$ 33,200	$ 31,200
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Interest Receivable	Interest Receivable
Total loans	$ 1,300
Amounts outstanding	610,000
Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss	10,353,251	$ 9,637,929
Foreclosures in progress	6,300	5,800
Sale of secondary market eligible residential consumer mortgage loans	58,800	6,100
Liabilities for off-balance-sheet
Beginning balance	913	1,123	$ 803
Charge-offs	0	0	0
Recoveries	0	0	0
Provision	219
Ending balance	1,132	913	1,123
Allowance for credit loss
PCD Allowance at Acquisition			0
Asset Pledged as Collateral \| Borrowings from FHLB and FRB
Allowance for credit loss - loans
Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss	6,720,000
Topic ASC 326
Liabilities for off-balance-sheet
Provision		(210)	320
Business lending
Allowance for credit loss - loans
Charge-offs		(784)
Consumer mortgage
Allowance for credit loss - loans
Charge-offs	(384)	(669)
Consumer indirect
Allowance for credit loss - loans
Charge-offs	(11,607)	(9,352)
Consumer direct
Allowance for credit loss - loans
Charge-offs	(2,744)	(2,009)
Home equity
Allowance for credit loss - loans
Charge-offs	(164)	(119)
Unallocated
Allowance for credit loss - loans
Beginning balance		1,000	1,000
Charge-offs			0
Recoveries			0
Provision			0
Ending balance			1,000
Allowance for credit loss
PCD Allowance at Acquisition			0
Commercial Portfolio Segment \| Business lending
Allowance for credit loss - loans
Beginning balance	26,854	23,297	22,995
Charge-offs			(824)
Recoveries			1,374
Provision			(319)
Ending balance		26,854	23,297
Allowance for credit loss
Charge-offs		(784)
Recoveries		523
PCD Allowance at Acquisition			71
Commercial Portfolio Segment \| Business lending \| Topic ASC 326
Allowance for credit loss - loans
Provision		3,818
Residential Portfolio Segment \| Consumer mortgage
Allowance for credit loss - loans
Beginning balance	15,333	14,343	10,017
Charge-offs	(384)	(669)	(313)
Recoveries	43	48	62
Provision	25		4,577
Ending balance	15,017	15,333	14,343
Allowance for credit loss
PCD Allowance at Acquisition			0
Residential Portfolio Segment \| Consumer mortgage \| Topic ASC 326
Allowance for credit loss - loans
Provision		1,611
Residential Portfolio Segment \| Home equity
Allowance for credit loss - loans
Beginning balance	1,628	1,594	1,814
Charge-offs	(164)	(119)	(86)
Recoveries	13	14	163
Provision	71		(297)
Ending balance	1,548	1,628	1,594
Allowance for credit loss
PCD Allowance at Acquisition			0
Residential Portfolio Segment \| Home equity \| Topic ASC 326
Allowance for credit loss - loans
Provision		139
Consumer Portfolio Segment \| Business lending
Allowance for credit loss - loans
Beginning balance	26,854
Charge-offs	(3,157)
Recoveries	425
Provision	13,079
Ending balance	37,201	26,854
Consumer Portfolio Segment \| Consumer indirect
Allowance for credit loss - loans
Beginning balance	18,585	17,852	11,737
Charge-offs	(11,607)	(9,352)	(7,986)
Recoveries	6,508	5,719	4,756
Provision	7,409		9,345
Ending balance	20,895	18,585	17,852
Allowance for credit loss
PCD Allowance at Acquisition			0
Consumer Portfolio Segment \| Consumer indirect \| Topic ASC 326
Allowance for credit loss - loans
Provision		4,366
Consumer Portfolio Segment \| Consumer direct
Allowance for credit loss - loans
Beginning balance	3,269	2,973	2,306
Charge-offs	(2,744)	(2,009)	(1,252)
Recoveries	958	826	772
Provision	1,970		1,147
Ending balance	3,453	3,269	2,973
Allowance for credit loss
PCD Allowance at Acquisition			0
Consumer Portfolio Segment \| Consumer direct \| Topic ASC 326
Allowance for credit loss - loans
Provision		1,479
Unallocated
Allowance for credit loss - loans
Beginning balance	1,000	1,000
Charge-offs	0	0
Recoveries	0	0
Provision	0
Ending balance	1,000	1,000	1,000
Unallocated \| Topic ASC 326
Allowance for credit loss - loans
Provision		0
Allowances for credit losses
Allowance for credit loss - loans
Charge-offs			(10,461)
Recoveries			7,127
Provision			14,453
Allowance for credit loss
Beginning balance	66,669	61,059	49,869
Charge-offs	(18,056)	(12,933)
Recoveries	7,947	7,130
PCD Allowance at Acquisition			71
Provision	22,554
Ending balance	79,114	66,669	61,059
Allowances for credit losses \| Topic ASC 326
Allowance for credit loss
Provision		11,413
Total allowances for credit losses
Allowance for credit loss - loans
Beginning balance	67,582	62,182	50,672
Charge-offs	(18,056)	(12,933)
Recoveries	7,947	7,130
Provision	22,773
Ending balance	$ 80,246	67,582	62,182
Allowance for credit loss
Charge-offs			(10,461)
Recoveries			7,127
PCD Allowance at Acquisition			71
Provision			$ 14,773
Total allowances for credit losses \| Topic ASC 326
Allowance for credit loss - loans
Provision		$ 11,203

Amount of Federal Home Loan Bank (FHLB) advances foreclosures in progress.

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