Derivatives and Hedging Activities - Narrative (Details)	3 Months Ended
	Mar. 31, 2019 USD ($) swap	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($) swap
Derivative [Line Items]
Accrued interest on derivatives, at fair value	$ 14,000		$ 65,000
Derivative, net liability position, aggregate fair value	6,100,000
Derivative, collateral, right to reclaim cash	9,100,000
Interest Rate Swap
Derivative [Line Items]
Derivative gain (loss) on derivative, net	67,000	$ 0
Not-designated hedge | Currency forward contract - non-designated hedge
Derivative [Line Items]
Notional amount of derivative	0		0
Not-designated hedge | Interest Rate Swap
Derivative [Line Items]
Notional amount of derivative	$ 68,700,000		$ 36,600,000
Number of swaps with customers offset by third party swaps | swap	4		3
Federal Home Loan Bank Advances | Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Notional amount of derivative	$ 385,000,000		$ 320,000,000
Number of interest rate derivatives held | swap	27		24