Derivative Instruments and Hedge Activities - Summary of Cash Flow Hedges (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional Amount	$ 344,726,000	$ 151,213,000
Derivative assets fair value	5,981,000	4,317,000
Derivative liabilities fair value	994,000	$ 559,000
Cash Flow Hedges
Derivative [Line Items]
Notional Amount	250,000,000
Derivative assets fair value	5,030,000
Derivative liabilities fair value	$ 38,000
Weighted average pay rates	1.67%
Weighted average receive rates	1.63%
Weighted average maturity	4 years 2 months 12 days