Derivatives (Effects of Derivative Instruments on the Statements of Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Derivative income reflected in income statement	$ 4,292	$ 8,692	$ 27,745	$ 36,412
Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedge [Member] | Interest Rate Swaps - Variable Rate Loans [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative income reflected in income statement	$ 1,752	$ 6,950	$ 14,519	$ 19,941
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Interest and Fee Income, Loans and Leases Held-in-portfolio	Interest and Fee Income, Loans and Leases Held-in-portfolio	Interest and Fee Income, Loans and Leases Held-in-portfolio	Interest and Fee Income, Loans and Leases Held-in-portfolio
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedging [Member] | Interest Income - Securities - Taxable [Member] | Interest Rate Swaps - Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative income reflected in income statement	$ 1,596	$ 21	$ 2,625	$ (6)
Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedging [Member] | Securities Transactions Net [Member] | Interest Rate Swaps - Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative income reflected in income statement	0	0	1,620	2,499
Derivatives Not Designated as Hedging Instruments [Member] | Secondary Mortgage Market Operations [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative income reflected in income statement	(365)	(1,249)	2,595	2,223
Derivatives Not Designated as Hedging Instruments [Member] | Other Noninterest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative income reflected in income statement	$ 1,309	$ 2,970	$ 6,386	$ 11,755