BORROWINGS - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Federal Home Loan Bank and Other Borrowings [Line Items]
Borrowings outstanding under BTFP	$ 1,745,000	$ 1,016,000
Federal Home Loan Bank of Des Moines
Federal Home Loan Bank and Other Borrowings [Line Items]
FHLB stock	55,300	49,300
Federal Reserve Bank Advances
Federal Home Loan Bank and Other Borrowings [Line Items]
Available borrowing capacity	710,000	340,000
Federal Home Loan Bank Advances \| Federal Home Loan Bank of Des Moines
Federal Home Loan Bank and Other Borrowings [Line Items]
Available borrowing capacity	2,100,000	$ 2,600,000
Bank Term Funding Program \| Federal Reserve Bank Advances
Federal Home Loan Bank and Other Borrowings [Line Items]
Borrowings outstanding under BTFP	645,000
Bank Term Funding Program \| Federal Reserve Bank Advances
Federal Home Loan Bank and Other Borrowings [Line Items]
Amount borrowed from Federal Reserve Bank	1,200,000
Amount repaid to Federal Reserve Bank	$ 535,000

Face (par) amount of debt instrument at time of issuance.

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