Loans - Additional Information (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2021 USD ($) payment	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2021 USD ($) loan payment	Dec. 31, 2020 USD ($) loan	Dec. 31, 2019 USD ($)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Paycheck protection program	$ 25,800,000				$ 208,900,000				$ 25,800,000	$ 208,900,000
Deferred loan costs	1,900,000				1,700,000				$ 1,900,000	1,700,000
Period of loan sold									30 days
Minimum period seldom held									90 days
Mortgage warehousing maximum pay off period									30 days
Nonaccrual interest income									$ 0	0
Non-accrual loans	14,962,000				22,142,000				14,962,000	22,142,000
Non-performing TDRs	1,500,000								1,500,000
TDR loans	$ 1,521,000				2,610,000				$ 1,521,000	2,610,000
Restructured loan returned to accruing status number of Consecutive Payments of loan | payment	6								6
Restructured loan reported in TDRs	$ 3,912,000				4,403,000				$ 3,912,000	4,403,000
Specific reserves allocated to troubled debt restructuring	0								0
Credit loss expense (recovery)	(2,071,000)	$ 1,112,000	$ (1,492,000)	$ 367,000	3,042,000	$ 2,052,000	$ 7,057,000	$ 8,600,000
Minimum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans with an aggregate credit exposure	3,000,000								$ 3,000,000
Loans classified as TDR after a period									90 days
Minimum | Good Pass
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of consecutive years of profit for Good Pass Rating									3 years
Number of consecutive years of profit Unaudited Financial Information for Good Pass Rating									5 years
Number of years of Satisfactory Relationship with bank for Good Pass Rating									5 years
Maximum
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans with an aggregate credit exposure	6,000,000								$ 6,000,000
Loans classified as TDR after a period									120 days
Maximum | Satisfactory Pass
Financing Receivable, Troubled Debt Restructuring [Line Items]
Minimum number of years of Satisfactory Repayment required for Satisfactory Pass Rating									2 years
CARES Act
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loan reported in TDRs	10,900,000				126,700,000				$ 10,900,000	126,700,000
Performing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured loan reported in TDRs	2,400,000				$ 1,800,000				$ 2,400,000	$ 1,800,000
Number TDRs returned to accrual status | loan									5	1
Loans Purchased With Evidence of Credit Deterioration
Financing Receivable, Troubled Debt Restructuring [Line Items]
Non-accrual loans	2,200,000								$ 2,200,000
Non-performing TDRs	$ 290,000								$ 290,000
Credit loss expense (recovery)											$ 133,000
Allowances for loan losses											$ 0