Revenue from Contracts with Customers Revenue from Contracts with Customers (Schedule of Contract with Customer, Asset and Liability) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Bank Card Transaction Fees [Member]
Contract with Customer, Asset and Liability [Line Items]
Contract with Customer, Receivable	$ 10,591	$ 13,315	$ 10,296	$ 14,686
Trust Fees [Member]
Contract with Customer, Asset and Liability [Line Items]
Contract with Customer, Receivable	2,533	2,802	2,680	2,681
Deposit Account Charges and Other Fees [Member]
Contract with Customer, Asset and Liability [Line Items]
Contract with Customer, Receivable	5,176	5,597	4,972	5,735
Consumer Brokerage Services [Member]
Contract with Customer, Asset and Liability [Line Items]
Contract with Customer, Receivable	$ 521	$ 380	$ 390	$ 309