Loans - Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Segment Based on Impairment Method (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Ending balance attributed to loans:
Collectively evaluated for impairment	$ 25,990	$ 26,612
Individually evaluated for impairment
Total ending balance of allowance	25,990	26,612
Ending balance of loans:
Collectively evaluated for impairment	1,589,738	1,415,035
Individually evaluated for impairment	41,052	54,748
Total ending balance of loans	1,630,790	1,469,783
Commercial Real Estate [Member]
Ending balance attributed to loans:
Collectively evaluated for impairment	11,231	10,090
Individually evaluated for impairment
Total ending balance of allowance	11,231	10,090
Ending balance of loans:
Collectively evaluated for impairment	580,561	525,579
Individually evaluated for impairment	12,915	25,207
Total ending balance of loans	593,476	550,786
Construction [Member]
Ending balance attributed to loans:
Collectively evaluated for impairment	4,641	3,949
Individually evaluated for impairment
Total ending balance of allowance	4,641	3,949
Ending balance of loans:
Collectively evaluated for impairment	87,432	70,007
Individually evaluated for impairment	879	4,720
Total ending balance of loans	88,311	74,727
Residential Real Estate [Member]
Ending balance attributed to loans:
Collectively evaluated for impairment	6,236	8,119
Individually evaluated for impairment
Total ending balance of allowance	6,236	8,119
Ending balance of loans:
Collectively evaluated for impairment	642,957	509,297
Individually evaluated for impairment	16,940	12,676
Total ending balance of loans	659,897	521,973
Commercial & Industrial [Member]
Ending balance attributed to loans:
Collectively evaluated for impairment	3,436	4,077
Individually evaluated for impairment
Total ending balance of allowance	3,436	4,077
Ending balance of loans:
Collectively evaluated for impairment	248,260	276,664
Individually evaluated for impairment	10,318	12,145
Total ending balance of loans	258,578	288,809
Lease Financing & Other [Member]
Ending balance attributed to loans:
Collectively evaluated for impairment	446	377
Individually evaluated for impairment
Total ending balance of allowance	446	377
Ending balance of loans:
Collectively evaluated for impairment	30,528	33,488
Individually evaluated for impairment
Total ending balance of loans	$ 30,528	$ 33,488