REVENUE FROM CONTRACTS WITH CUSTOMERS - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 5,598	$ 5,684	$ 12,079	$ 10,606
Products and services transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenue	2,620	2,767	5,892	5,034
Products and services transferred over time
Disaggregation of Revenue [Line Items]
Revenue	2,978	2,917	6,187	5,572
Trust management fees
Disaggregation of Revenue [Line Items]
Revenue	2,892	2,794	5,938	5,319
Financial services fees
Disaggregation of Revenue [Line Items]
Revenue	267	272	590	505
Interchange fees
Disaggregation of Revenue [Line Items]
Revenue	1,463	1,213	3,200	2,244
Customer deposit fees
Disaggregation of Revenue [Line Items]
Revenue	789	1,026	1,899	1,933
Other customer service fees
Disaggregation of Revenue [Line Items]
Revenue	$ 187	$ 379	$ 452	$ 605