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Business Combinations and Asset Acquisitions - Pro Forma (Details) - Umpqua Bank and Columbia Banking System Merger - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Asset Acquisition [Line Items]
Business acquisition, pro forma net interest income	$ 1,014,447	$ 959,039
Business Acquisition, Pro Forma Non-interest Income	128,250	179,091
Business Acquisition, Pro Forma Net Income (Loss)	381,212	$ 185,660
Business Combination, Acquisition Related Costs - Combined for proforma	$ 173,500

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 15
-Paragraph 3
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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479328/805-10-50-2

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