CREDIT QUALITY ASSESSMENT (Additional Information) (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable Troubled Debt Restructurings Specific Allowance	$ 563	$ 247
Other real estate owned	2,118	2,253
Mortgage Loans in Process of Foreclosure, Amount	0
Non-accrual loans	29,096	26,336
Consumer Portfolio Segment [Member] | WashingtonFirst Bankshares Inc [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	1,300
Restructured Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable Troubled Debt Restructurings Specific Allowance	600	200
Additional Financing Receivable Troubled Debt Restructurings Restructured	$ 1,600	$ 2,100