Loans Receivable, Credit Quality for Loans and the Allowance for Loan Losses - Summary of Unpaid Principal Balances and Related Carrying Amounts of Acquired Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Union Bank [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance	$ 44,950	$ 51,240
Carrying Amount	43,299	48,391
Union Bank [Member] | Credit Impaired Purchased Loans Evaluated Individually for Incurred Credit Losses [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance	1,303	1,478
Carrying Amount	580	668
Union Bank [Member] | Other Purchased Loans Evaluated Collectively for Incurred Credit Losses [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance	43,647	49,762
Carrying Amount	42,719	47,723
Citizens National Bank of Meyersdale [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance	52,543	58,189
Carrying Amount	52,108	57,862
Citizens National Bank of Meyersdale [Member] | Credit Impaired Purchased Loans Evaluated Individually for Incurred Credit Losses [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance	610	608
Carrying Amount	431	440
Citizens National Bank of Meyersdale [Member] | Other Purchased Loans Evaluated Collectively for Incurred Credit Losses [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance	51,933	57,581
Carrying Amount	$ 51,677	$ 57,422