Guarantees (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2020	Dec. 31, 2019
Guarantor Obligations [Line Items]
Derivative Liabilities	[1]	$ 20,370	$ 10,219
Notional amount of underlying interest rate swaps associated with risk participation agreements		3,548,498	$ 4,525,856
Financial Standby Letter Of Credit [Member]
Guarantor Obligations [Line Items]
Standby letters of credit, net liability		3,300
Contractual amount of letters of credit, guaranteed maximum potential future payments		318,000
Risk Participation Agreement [Member] | Indirect Guarantee Of Indebtedness [Member]
Guarantor Obligations [Line Items]
Derivative Liabilities		1,200
Notional amount of underlying interest rate swaps associated with risk participation agreements		$ 272,800
Minimum [Member] | Risk Participation Agreement [Member]
Guarantor Obligations [Line Items]
Term, in years		2 years
Maximum [Member] | Risk Participation Agreement [Member]
Guarantor Obligations [Line Items]
Term, in years		11 years

[1] * The fair value of each class of derivative is shown in Note 11.