Revenue from Contracts with Customers (Schedule of Disaggregation of Revenue) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Non-interest income		$ 142,949	$ 138,514	$ 428,166	$ 409,710
Total non-interest income from contracts with customers
Disaggregation of Revenue [Line Items]
Non-interest income		134,928	130,010	395,872	383,161
Total non-interest income from contracts with customers | Bank card transaction fees
Disaggregation of Revenue [Line Items]
Non-interest income		46,899	45,638	143,278	131,556
Total non-interest income from contracts with customers | Trust fees
Disaggregation of Revenue [Line Items]
Non-interest income		49,207	45,406	141,800	140,009
Total non-interest income from contracts with customers | Deposit account charges and other fees
Disaggregation of Revenue [Line Items]
Non-interest income		23,090	24,521	67,475	72,392
Total non-interest income from contracts with customers | Consumer brokerage services
Disaggregation of Revenue [Line Items]
Non-interest income		3,820	5,085	13,582	14,599
Total non-interest income from contracts with customers | Other non-interest income
Disaggregation of Revenue [Line Items]
Non-interest income		11,912	9,360	29,737	24,605
Other non-interest income (1)
Disaggregation of Revenue [Line Items]
Non-interest income	[1]	$ 8,021	$ 8,504	$ 32,294	$ 26,549

[1] This revenue is not within the scope of ASC 606, and includes fees relating to capital market activities, loan fees and sales, derivative instruments, standby letters of credit and various other transactions.