Loans, Leases and Other Real Estate - Company's Non-Performing Assets and Its Accruing Troubled Debt Restructurings (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	$ 13,545	$ 20,404
Other real estate and other repossessed assets	1,168	1,072
TOTAL NON-PERFORMING ASSETS	14,713	21,476
Troubled debt restructurings, still accruing	11,279	8,802
Commercial, Secured by Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	5,348	10,413
Commercial, Industrial and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	172	167
Leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	110	153
Real Estate - Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	4,410	6,048
Real Estate-Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	1,472	1,472
Home Equity and Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	$ 2,033	$ 2,151