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Loans and Allowance for Credit Losses - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($) loan	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) loan	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) loan
Financing Receivable, Past Due [Line Items]
Loans greater than 90 days past due	$ 0		$ 0		$ 0
Number of collateral dependent loans in process of foreclosure | loan	0		0		0
Interest income related to non-accrual loans	$ 0	$ 0	$ 0	$ 0
Foregone interest income related to non-accrual loans	38,200	$ 26,100	77,400	$ 35,300
Pledged loans	1,600,000,000		1,600,000,000		$ 1,700,000,000
Federal Reserve Bank of San Francisco
Financing Receivable, Past Due [Line Items]
FRB pledged loans	$ 1,200,000,000		$ 1,200,000,000		$ 1,200,000,000

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