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ALLOWANCE FOR CREDIT LOSSES FOR LOANS AND FINANCE LEASES - Carrying Amount of Portfolios (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	$ 12,746,556	$ 12,185,483
Allowance for credit losses	243,942	261,843	$ 260,464	$ 269,030
Residential Mortgage Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	2,828,431	2,821,726
Allowance for credit losses	$ 40,654	$ 57,397	62,760	74,837
Residential Mortgage Loans [Member] \| Allowance for loan and lease losses, numerator [Member] \| Loans Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	1.44%	2.03%
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	$ 228,396	$ 214,777
Allowance for credit losses	$ 3,824	$ 5,605	2,308	4,048
Commercial Portfolio Segment [Member] \| Construction Loans [Member] \| Allowance for loan and lease losses, numerator [Member] \| Loans Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	1.67%	2.61%
Commercial Portfolio Segment [Member] \| Commercial Mortgage Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	$ 2,565,984	$ 2,317,083
Allowance for credit losses	$ 22,447	$ 32,631	35,064	52,771
Commercial Portfolio Segment [Member] \| Commercial Mortgage Loans [Member] \| Allowance for loan and lease losses, numerator [Member] \| Loans Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	0.87%	1.41%
Commercial Portfolio Segment [Member] \| Commercial and Industrial Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	$ 3,366,038	$ 3,174,232
Allowance for credit losses	$ 32,266	$ 33,190	32,906	34,284
Commercial Portfolio Segment [Member] \| Commercial and Industrial Loans [Member] \| Allowance for loan and lease losses, numerator [Member] \| Loans Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	0.96%	1.05%
Consumer Portfolio Segment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	$ 3,757,707	$ 3,657,665
Allowance for credit losses	$ 144,751	$ 133,020	$ 127,426	$ 103,090
Consumer Portfolio Segment [Member] \| Allowance for loan and lease losses, numerator [Member] \| Loans Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	3.85%	3.64%
Loan Total [Member] \| Allowance for loan and lease losses, numerator [Member] \| Loans Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	1.91%	2.15%