Business Combinations narrative (Details) - Pacific Continental [Member] - USD ($) $ in Thousands		12 Months Ended
	Nov. 01, 2017	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Business Combination, Purchase Price Allocation, Junior Subordinated Debentures	$ (14,434)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(2,300,491)
Business Combination, Purchase Price Allocation, Goodwill Amount	$ 383,080
Business Acquisition, Effective Date of Acquisition	Nov. 01, 2017
Business Combination, Cost of Acquired Entity, Purchase Price, Total	$ 637,103
Business Combination, Acquired Receivable, Fair Value	1,873,987
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	254,023
Business Combination, Purchase Price Allocation, Amortizable Intangible Assets	46,875
Business Combination, Acquisition Related Costs		$ 0	$ 8,661
Business Combination, Purchase Price Allocation, Other Assets	50,638
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	2,554,514
Business Acquisition, Purchase Price Allocation, Liabilities, Deposits	$ 2,118,982
Business Acquisition, Percentage of Voting Interests Acquired	100.00%
Business Combination, Purchase Price Allocation, Federal Home Loan bank advances	$ (101,127)