Derivative Instruments and Hedging Activities - Amount of Gain or Loss Recognized in Income on Derivatives (Details) - Not Designated as Hedging Instruments - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives (Loss)/Gain	$ (1)	$ 230
Interest rate swap contracts—commercial loans
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives (Loss)/Gain	(122)	145
Interest rate lock commitments—mortgage loans
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives (Loss)/Gain	88	25
Forward sale contracts—mortgage loans
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives (Loss)/Gain	$ 33	$ 60