BORROWINGS - Narrative (Detail) - USD ($)	Mar. 15, 2022	Nov. 05, 2019	Dec. 31, 2023	Dec. 31, 2022
Subordinated debentures [Line Items]:
Subordinated debt			$ 370,803,000	$ 370,205,000
Percentage of principal and accrued interest of retail repurchase agreements collateralized			102.50%
FHLB availability			$ 3,100,000,000	2,600,000,000
FHLB advances outstanding			550,000,000	550,000,000
Federal Home Loan Bank Advances
Subordinated debentures [Line Items]:
Line of credit amount available for borrowing			3,600,000,000	3,200,000,000
Federal Reserve and Correspondent Banks
Subordinated debentures [Line Items]:
Line of credit amount available for borrowing			651,300,000	718,600,000
Long-term line of credit			0	0
Unsecured lines of credit, correspondent banks
Subordinated debentures [Line Items]:
Line of credit amount available for borrowing			1,200,000,000	1,600,000,000
Long-term line of credit			0	260,000,000
Residential Mortgage | Asset Pledged as Collateral | Federal Home Loan Bank Advances | Federal Home Loan Bank Advances
Subordinated debentures [Line Items]:
Line of credit amount available for borrowing			1,400,000,000	1,200,000,000
Commercial real estate loans | Asset Pledged as Collateral | Federal Home Loan Bank Advances | Federal Home Loan Bank Advances
Subordinated debentures [Line Items]:
Line of credit amount available for borrowing			4,000,000,000	3,600,000,000
HELOC | Asset Pledged as Collateral | Federal Home Loan Bank Advances | Federal Home Loan Bank Advances
Subordinated debentures [Line Items]:
Line of credit amount available for borrowing			209,200,000	214,300,000
Multifamily Loans | Asset Pledged as Collateral | Federal Home Loan Bank Advances | Federal Home Loan Bank Advances
Subordinated debentures [Line Items]:
Line of credit amount available for borrowing			$ 538,600,000	$ 514,800,000
Subordinated Debt | Fixed Floating Rate Subordinated Notes Due 2032
Subordinated debentures [Line Items]:
Subordinated debt	$ 200,000,000
Interest rate	3.875%		3.875%
Basis spread on variable rate	1.965%
Unamortized discount (premium) and debt issuance costs, net	$ 3,100,000
Subordinated Debt | Fixed Floating Rate Subordinated Notes Due 2029
Subordinated debentures [Line Items]:
Subordinated debt		$ 175,000,000
Interest rate		4.25%	4.25%
Basis spread on variable rate		2.88%
Unamortized discount (premium) and debt issuance costs, net		$ 2,900,000
Subordinated Debt | Fixed Floating Rate Subordinated Notes Due 2029 | Benchmark Adjustment
Subordinated debentures [Line Items]:
Basis spread on variable rate		0.26%