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Business Combination - Merger related expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Asset Acquisition [Line Items]
Business Combination, Acquisition Related Costs - Communication	$ 0	$ 20,000
Umpqua Bank and Columbia Banking System Merger
Asset Acquisition [Line Items]
Business combination, acquisition related costs, Legal and Professional Fees	375	61,857
Business Combination, Acquisition Related Costs - Personnel	9,436	38,265
Business Combination, Acquisition Related Costs - Premises and Equipment	1,027	45,374
Business Combination, Acquisition Related Costs - Other	0	6,163
Business Combination, Acquisition Related Costs	$ 10,838	$ 171,659

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- Definition

Business Combination, Acquisition Related Costs - Communication

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Business combination, acquisition related costs, Legal and Professional Fees

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Business Combination, Acquisition Related Costs - Premises and Equipment

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- 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.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 15
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480123/805-50-15-3

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This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479405/805-10-25-23

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