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Business Combinations and Asset Acquisitions - Schedule of hypothetical number of shares (Details) - Umpqua Bank and Columbia Banking System Merger shares in Thousands | Feb. 28, 2023 shares
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Asset Acquisition [Line Items] |
Business Acquisition Hypothetical Equity Interests Issued or Issuable | 349,515
Business Acquisition Hypothetical Percentage of Voting Interests Acquired | 1.000
Columbia Banking System, Inc. |
Asset Acquisition [Line Items] |
Business Acquisition Hypothetical Equity Interests Issued or Issuable | 132,365
Business Acquisition Hypothetical Percentage of Voting Interests Acquired | 0.379
UHC |
Asset Acquisition [Line Items] |
Business Acquisition Hypothetical Equity Interests Issued or Issuable | 217,150
Business Acquisition Hypothetical Percentage of Voting Interests Acquired | 0.621

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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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