Guarantees (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2020	Dec. 31, 2019
Guarantor Obligations [Line Items]
Derivative Liabilities	[1]	$ 21,373	$ 10,219
Notional amount of underlying interest rate swaps associated with risk participation agreements		4,607,919	$ 4,525,856
Financial Standby Letter Of Credit [Member]
Guarantor Obligations [Line Items]
Standby letters of credit, net liability		2,400
Contractual amount of letters of credit, guaranteed maximum potential future payments		428,000
Risk Participation Agreement [Member] | Indirect Guarantee Of Indebtedness [Member]
Guarantor Obligations [Line Items]
Derivative Liabilities		1,100
Notional amount of underlying interest rate swaps associated with risk participation agreements		$ 294,300
Minimum [Member] | Risk Participation Agreement [Member]
Guarantor Obligations [Line Items]
Term, in years		1 year
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.