Loans, Leases and Other Real Estate - Company's Non-Performing Assets and Its Accruing Troubled Debt Restructurings (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	$ 13,345	$ 13,655
Other real estate and other repossessed assets	1,392	843
TOTAL NON-PERFORMING ASSETS	14,737	14,498
Troubled debt restructurings, still accruing	9,526	11,462
Commercial, secured by real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	4,732	5,890
Commercial, industrial and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	1,505	184
Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	250	144
Real estate - residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	3,045	3,860
Real estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	1,472	1,472
Home equity and consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	$ 2,341	$ 2,105