ALLOWANCE FOR CREDIT LOSSES ON LOANS AND FINANCE LEASES - Carrying Amount of Portfolios (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	$ 11,577,985	$ 11,552,825
Allowance for credit losses	265,567	260,464	$ 245,447	$ 269,030
Residential Mortgage Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	2,811,528	2,847,290
Allowance for credit losses	$ 64,403	$ 62,760	68,820	74,837
Residential Mortgage Loans [Member] | Allowance for loan and lease losses, numerator [Member] | Amortized cost, denominator [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	2.29%	2.20%
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	$ 2,862,189	$ 2,886,263
Allowance for credit losses	$ 31,235	$ 32,906	36,784	34,284
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member] | Allowance for loan and lease losses, numerator [Member] | Amortized cost, denominator [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	1.09%	1.14%
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	$ 2,353,659	$ 2,358,851
Allowance for credit losses	$ 36,460	$ 35,064	30,138	52,771
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Allowance for loan and lease losses, numerator [Member] | Amortized cost, denominator [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	1.55%	1.49%
Commercial Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	$ 143,664	$ 132,953
Allowance for credit losses	$ 3,231	$ 2,308	1,842	4,048
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Allowance for loan and lease losses, numerator [Member] | Amortized cost, denominator [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	2.25%	1.74%
Consumer Portfolio Segment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Amortized cost of loans	$ 3,406,945	$ 3,327,468
Allowance for credit losses	$ 130,238	$ 127,426	$ 107,863	$ 103,090
Consumer Portfolio Segment [Member] | Allowance for loan and lease losses, numerator [Member] | Amortized cost, denominator [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	3.82%	3.83%
Loan Total [Member] | Allowance for loan and lease losses, numerator [Member] | Amortized cost, denominator [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses to amortized cost	2.29%	2.25%