Derivatives and Hedging Activities - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($) swap	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) swap	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) swap
Derivative [Line Items]
Accrued interest on derivatives, at fair value	$ 1,100,000		$ 1,100,000		$ 344,000
Derivative, net liability position, aggregate fair value	24,500,000		24,500,000
Derivative, collateral, right to reclaim cash	47,100,000		47,100,000
Interest Rate Swap
Derivative [Line Items]
Derivative gain (loss) on derivative, net	(44,000)	$ 75,000	406,000	$ 288,000
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	$ 170,900,000		$ 170,900,000		$ 169,900,000
Number of commercial banking customers | swap	46		46		22
Federal Home Loan Bank Advances | Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Notional amount of derivative	$ 445,000,000.0		$ 445,000,000.0		$ 410,000,000.0
Number of interest rate derivatives held | swap	32		32		29