Business Combinations and Asset Acquisitions - Merger related expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Asset Acquisition [Line Items]
Business Combination, Acquisition Related Costs - Communication	$ 20,000
Merger related expenses	115,898	$ 2,278
Umpqua Bank and Columbia Banking System Merger
Asset Acquisition [Line Items]
Business combination, acquisition related costs, Legal and Professional Fees	49,419
Business Combination, Acquisition Related Costs - Personnel	21,455
Business Combination, Acquisition Related Costs - Premises and Equipment	21,265
Business Combination, Acquisition Related Costs - Other	3,759
Merger related expenses	$ 115,898