LOANS AND ALLOWANCE FOR LOAN LOSSES (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) agreement	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Accounts Notes And Loans Receivable [Line Items]
Unpaid principal balance of loans	$ 23,849	$ 17,370
Total loans	2,185,635	2,178,961
Loans reclassified within portfolio classifications	33,900
Mortgage loans on real estate, foreclosures	1,400	1,200
Mortgage loans in process of foreclosure, amount	1,900	1,500
SBA guaranteed amounts included in nonaccrual loans	4,100	3,400
Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Accretable discount on loans	3,900	4,500	$ 3,900
Doubtful [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans	0	0
Eastern Virginia Bankshares Inc and Greater Atlantic Bank and Harvest Bank of Maryland and Prince George Federal Savings Bank [Member]
Accounts Notes And Loans Receivable [Line Items]
Accretable discount on loans	11,200	15,100
GAB acquisition [Member]
Accounts Notes And Loans Receivable [Line Items]
Loss sharing agreement	143,400
Total loans	620,368	$ 807,208
Federal Deposit Insurance Corporation [Member] | GAB acquisition [Member]
Accounts Notes And Loans Receivable [Line Items]
Loss sharing agreement	$ 143,400
Number of agreements | agreement	2
Federal Deposit Insurance Corporation [Member] | GAB acquisition [Member] | Single Family Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Term loan agreement expiring	10 years
Federal Deposit Insurance Corporation [Member] | GAB acquisition [Member] | Non Single Family Commercial [Member]
Accounts Notes And Loans Receivable [Line Items]
Term loan agreement expiring	5 years