Derivatives (Net Gains (Losses) on Derivatives Designated as Hedges) (Details) - Derivative instruments designated as hedging instruments - Fair Value Hedging - Interest Expense - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Certificates of deposits
Derivative [Line Items]
Recognized on certificates of deposit	$ 278	$ 2,271	$ 157
Interest rate contracts
Derivative [Line Items]
Recognized on interest rate swaps	$ (93)	$ (2,734)	$ (794)