Revenue from Contracts with Customers Revenue from Contracts with Customers (Schedule of Contract with Customer, Asset and Liability) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Bank Card Transaction Fees [Member]
Contract with Customer, Asset and Liability [Line Items]
Contract with Customer, Receivable	$ 11,104	$ 13,315	$ 10,878	$ 14,686
Trust Fees [Member]
Contract with Customer, Asset and Liability [Line Items]
Contract with Customer, Receivable	2,893	2,802	3,227	2,681
Deposit Account Charges and Other Fees [Member]
Contract with Customer, Asset and Liability [Line Items]
Contract with Customer, Receivable	5,773	5,597	5,471	5,735
Consumer Brokerage Services [Member]
Contract with Customer, Asset and Liability [Line Items]
Contract with Customer, Receivable	$ 924	$ 380	$ 345	$ 309