Guarantees (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Guarantor Obligations [Line Items]
Derivative Liabilities	$ 10,012	$ 13,421
Notional amount of underlying interest rate swaps associated with risk participation agreements	3,956,374	$ 3,254,921
Financial Standby Letter Of Credit [Member]
Guarantor Obligations [Line Items]
Standby letters of credit, net liability	2,000
Contractual amount of letters of credit, guaranteed maximum potential future payments	355,000
Risk Participation Agreement [Member] | Indirect Guarantee Of Indebtedness [Member]
Guarantor Obligations [Line Items]
Derivative Liabilities	177
Notional amount of underlying interest rate swaps associated with risk participation agreements	$ 76,000
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