Derivatives - Narrative (Details)	3 Months Ended	12 Months Ended
	Sep. 30, 2017 USD ($)	Dec. 31, 2019 USD ($) derivative_swap	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Derivatives, Fair Value [Line Items]
Threshold for collateral requirements		$ 250,000
Collateral posted		4,700,000	$ 296,000
Notional amount		$ 94,400,000	16,000,000
Number of instruments | derivative_swap		16
Interest rate swap income		$ 964,000	84,000	$ 26,000
Commitments to originate loans held for sale		48,796,000	44,999,000
RML
Derivatives, Fair Value [Line Items]
Commitments to originate loans held for sale		48,800,000	45,000,000
Variable to Fixed
Derivatives, Fair Value [Line Items]
Notional amount		$ 47,200,000
Number of instruments | derivative_swap		8
Fixed to Variable
Derivatives, Fair Value [Line Items]
Notional amount		$ 47,200,000
Number of instruments | derivative_swap		8
Interest rate swaps | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Cash pledged to collateralize fair value exposure on interest rate swap		$ 1,300,000	400,000
Unrealized gain (loss) on interest rate swap		$ (534,000)	$ 607,000
Subordinated Debt
Derivatives, Fair Value [Line Items]
Junior subordinated debenture	$ 10,000,000.0
Effective interest rate on junior subordinated debenture	3.72%
Debt instrument, interest rate during period		3.26%
Subordinated Debt | LIBOR
Derivatives, Fair Value [Line Items]
Debt instrument, basis spread on variable rate	1.37%