Acquisitions (Acquisition Related Costs) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Business Acquisition [Line Items]
Total merger-related expense	$ 0	$ 49,738
FCB Financial Holdings, Inc.
Business Acquisition [Line Items]
Total merger-related expense		49,738
FCB Financial Holdings, Inc. | Employment compensation agreements, severance, and other employee benefit costs
Business Acquisition [Line Items]
Total merger-related expense		32,988
FCB Financial Holdings, Inc. | Professional fees
Business Acquisition [Line Items]
Total merger-related expense		15,200
FCB Financial Holdings, Inc. | All other expense
Business Acquisition [Line Items]
Total merger-related expense		$ 1,550