Derivatives and Hedging Activities - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) swap	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) swap	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) swap
Derivative [Line Items]
Accrued interest on derivatives, at fair value	$ 846,000		$ 846,000		$ 344,000
Derivative, net liability position, aggregate fair value	28,500,000		28,500,000
Derivative, collateral, right to reclaim cash	49,900,000		49,900,000
Interest Rate Swap
Derivative [Line Items]
Derivative gain (loss) on derivative, net	24,000	$ 146,000	450,000	$ 213,000
Not-designated hedge | Currency forward contract - non-designated hedge
Derivative [Line Items]
Notional amount of derivative	0		0		0
Not-designated hedge | Interest Rate Swap
Derivative [Line Items]
Notional amount of derivative	$ 171,300,000		$ 171,300,000		$ 169,900,000
Number of commercial banking customers | swap	23		23		22
Federal Home Loan Bank Advances | Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Notional amount of derivative	$ 475,000,000.0		$ 475,000,000.0		$ 410,000,000.0
Number of interest rate derivatives held | swap	34		34		29