Derivative Instruments and Hedging Activities - Amount of Gain or Loss Recognized in Income on Derivatives (Details) - Not Designated as Hedging Instruments - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivative Gain/ (Loss)	$ 230	$ 58	$ (63)
Interest Rate Swap Contracts—Commercial Loans
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivative Gain/ (Loss)	145	17	(16)
Interest Rate Lock Commitments—Mortgage Loans
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivative Gain/ (Loss)	25	(11)	(25)
Forward Sale Contracts—Mortgage Loans
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivative Gain/ (Loss)	$ 60	$ 52	$ (22)