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Business Combinations and Asset Acquisitions - Merger related expense (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Asset Acquisition [Line Items] |  |  |
Business Combination, Acquisition Related Costs - Communication | $ 20,000 | $ 0 |
Merger-related expenses | 171,659 | 17,356 | $ 15,183
Umpqua Bank and Columbia Banking System Merger |  |  |
Asset Acquisition [Line Items] |  |  |
Business combination, acquisition related costs, Legal and Professional Fees | 61,857 | 6,202 |
Business Combination, Acquisition Related Costs - Personnel | 38,265 | 1,124 |
Business Combination, Acquisition Related Costs - Premises and Equipment | 45,374 | 9,374 |
Business Combination, Acquisition Related Costs - Other | 6,163 | 656 |
Merger-related expenses | $ 171,659 | $ 17,356 |

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- Definition Business Combination, Acquisition Related Costs - Communication + References No definition available. + Details
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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 + Details
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- Definition 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 + Details
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- Details
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