Derivative Financial Instruments (Other free standing derivatives) (Balance sheet category and fair values) (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Other assets | Interest rate lock commitments (mortgage)
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	$ 65,591	$ 53,588
Fair Value, Other Assets	1,959	1,738
Other assets | Forward commitments
Derivatives, Fair Value [Line Items]
Notional Amount, Other Assets	55,118	37,286
Fair Value, Other Assets	283	80
Other liabilities | Forward commitments
Derivatives, Fair Value [Line Items]
Notional Amount, Other Liabilities	91,625	118,632
Fair Value, Other Liabilities	(320)	(232)
Other liabilities | Undesignated interest rate swaps
Derivatives, Fair Value [Line Items]
Notional Amount, Other Liabilities	13,907	14,045
Fair Value, Other Liabilities	$ (461)	$ (738)