Business Combinations and Asset Acquisitions - acquisition-related expenses (Details) - Bank of Commerce - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Asset Acquisition [Line Items]
Business Combination, Acquisition Related Costs	$ 10,370	$ 0	$ 0
Compensation and employee benefits [Member]
Asset Acquisition [Line Items]
Business Combination, Acquisition Related Costs	4,875	0	0
Occupancy [Member]
Asset Acquisition [Line Items]
Business Combination, Acquisition Related Costs	271	0	0
Data processing [Member]
Asset Acquisition [Line Items]
Business Combination, Acquisition Related Costs	287	0	0
Legal and professional fees [Member]
Asset Acquisition [Line Items]
Business Combination, Acquisition Related Costs	4,429	0	0
Advertising and promotion [Member]
Asset Acquisition [Line Items]
Business Combination, Acquisition Related Costs	9	0	0
Other noninterest expenses [Member]
Asset Acquisition [Line Items]
Business Combination, Acquisition Related Costs	$ 499	$ 0	$ 0