Derivatives (Net Gains (Losses) on Derivatives Designated as Hedges) (Details) - Fair Value Hedging - Derivative instruments designated as hedging instruments - Interest Expense - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Certificates of deposits
Derivative [Line Items]
Recognized on certificates of deposit	$ (1,261)	$ 1,279
Interest rate contracts
Derivative [Line Items]
Recognized on interest rate swaps	$ 1,220	$ (1,452)