Loans - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) payment contract	Dec. 31, 2018 USD ($) payment contract	Dec. 31, 2017 USD ($) payment contract
Receivables [Abstract]
Reduction in interest income	$ 400,000	$ 1,000,000.0	$ 700,000
Loans to directors and executive officers	1,700,000	$ 900,000
New loans offered	$ 0
Number of loans modified in troubled debt restructurings | contract	9	4	1
Value of loans modified in troubled debt restructurings	$ 4,700,000	$ 200,000	$ 100,000
Payments for loans in default, number of payments | payment	4	0	0
Payments for loans in default	$ 3,200,000
Accruals for trouble debt restructurings	11,100,000	$ 13,300,000
Average amount for loans impaired	35,600,000	35,300,000	$ 30,900,000
Interest income on impaired loans	2,000,000.0	2,000,000.0	1,500,000
Interest income related to impaired loans with impairment measured on present value of expected future cash flows	$ 100,000	$ 200,000	$ 300,000