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BUSINESS COMBINATION - Summary of Amount of Expenses Related to Merger (Details) - Mechanics Bank Acquisition - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2025
Business Combination [Line Items]
Business combination, acquisition-related cost, expense	$ 63,869	$ 69,858
Severance and employee related
Business Combination [Line Items]
Business combination, acquisition-related cost, expense	27,795	27,795
Legal and professional
Business Combination [Line Items]
Business combination, acquisition-related cost, expense	11,947	17,683
System conversion, integration and other
Business Combination [Line Items]
Business combination, acquisition-related cost, expense	$ 24,127	$ 24,380

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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