SBA AND USDA LOAN SERVICING - Other information (Details)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
SBA And USDA Loan
SBA AND USDA LOAN SERVICING
Unpaid principal balances of serviced loans	$ 549,800,000	$ 507,400,000
Aggregate fair market value of the interest only strips included in SBA servicing assets	$ 161,000	$ 155,000
Discount Rate
SBA AND USDA LOAN SERVICING
Measurement input of servicing rights	13.5	14
Prepayment speed
SBA AND USDA LOAN SERVICING
Measurement input of servicing rights	21.9	20.7
Minimum | Discount Rate | SBA And USDA Loan
SBA AND USDA LOAN SERVICING
Measurement input of servicing rights	4.55	4.67
Minimum | Prepayment speed | SBA And USDA Loan
SBA AND USDA LOAN SERVICING
Measurement input of servicing rights	14.89	14.04
Maximum | Discount Rate | SBA And USDA Loan
SBA AND USDA LOAN SERVICING
Measurement input of servicing rights	10.18	10.89
Maximum | Prepayment speed | SBA And USDA Loan
SBA AND USDA LOAN SERVICING
Measurement input of servicing rights	19.69	17.71