Loans and Loans Held for Sale - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014 Property	Mar. 31, 2013 SecurityLoan	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unearned income on loans	$ 1,200,000		$ 1,300,000
Percentage of commercial loans in total portfolio loans	73.00%		73.00%
Maximum concentration of commercial real estate and commercial construction portfolio in loans	9.00%		9.00%
Number of TDRs returned back to accruing status		1
Financial receivable trouble debt restructuring reclassified to accruing trouble debt restructuring status		200,000
Commitment to lend additional funds on TDRs	0
Minimum period of loan payment defaults following restructure for TDRs to be in default	90 days
Other real estate owned properties	6
Commercial Real Estate and Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Combined percentage of commercial real estate and commercial construction in total commercial loans	67.00%		68.00%
Combined percentage of commercial real estate and commercial construction in total portfolio loans	49.00%		49.00%
Out-of-state exposure of combined portfolio	24.00%		23.00%
Percentage of total loans out-of-state	12.00%		11.00%
Out-of-state exposure of combined portfolio excluding contiguous states	7.30%		7.90%
Percentage of total loans out-of-state excluding contiguous states	3.60%		3.90%
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified not considered to be troubled debt restructuring	$ 400,000