Derivative Instruments and Hedging Activities - Schedule of Derivative Instruments (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Derivative Asset [Abstract]
Notional Amount	$ 310,177	$ 139,337
Fair Value	6,383	1,916
Derivative Liability [Abstract]
Notional Amount	275,094	125,526
Fair Value	6,270	1,898
Customer derivatives – interest rate swaps
Derivative Asset [Abstract]
Notional Amount	274,541	124,627
Fair Value	6,318	1,895
Derivative Liability [Abstract]
Notional Amount	274,541	124,627
Fair Value	6,269	1,895
RPAs sold
Derivative Asset [Abstract]
Notional Amount	0	0
Fair Value	0	0
Derivative Liability [Abstract]
Notional Amount	553	899
Fair Value	1	3
RPAs purchased
Derivative Asset [Abstract]
Notional Amount	35,636	14,710
Fair Value	65	21
Derivative Liability [Abstract]
Notional Amount	0	0
Fair Value	$ 0	$ 0