Estimated Fair Value of Financial Instruments - Summary of Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Accrued interest payable	$ 882	$ 1,118
Carrying Value [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Cash and due from banks, Federal funds sold and interest bearing deposits in other banks	30,659	40,647
Securities	203,763	226,012
Restricted stock	5,741	0
Portfolio loans, net	864,911	826,025
Loans held for sale	7,634	3,448
Accrued interest receivable	3,726	3,550
Demand, savings and money market	517,181	486,690
Certificates of deposit	482,411	504,390
Short-term borrowings	1,115	227
Federal Home Loan Bank advances	46,508	42,497
Junior subordinated debentures	16,238	16,238
Accrued interest payable	882	1,118
Estimated Fair Value [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Cash and due from banks, Federal funds sold and interest bearing deposits in other banks	30,659	40,647
Securities	203,763	226,012
Restricted stock	5,741	0
Portfolio loans, net	868,716	825,662
Loans held for sale	7,891	3,448
Accrued interest receivable	3,726	3,550
Demand, savings and money market	511,665	486,690
Certificates of deposit	485,394	509,449
Short-term borrowings	1,115	227
Federal Home Loan Bank advances	46,828	43,824
Junior subordinated debentures	17,197	16,130
Accrued interest payable	882	1,118
Level 1 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Cash and due from banks, Federal funds sold and interest bearing deposits in other banks	30,659
Securities
Restricted stock
Portfolio loans, net
Loans held for sale
Accrued interest receivable
Demand, savings and money market
Certificates of deposit
Short-term borrowings
Federal Home Loan Bank advances
Junior subordinated debentures
Accrued interest payable
Level 2 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Cash and due from banks, Federal funds sold and interest bearing deposits in other banks
Securities	203,763
Restricted stock	5,741
Portfolio loans, net
Loans held for sale	7,891
Accrued interest receivable	3,726
Demand, savings and money market	511,665
Certificates of deposit	485,394
Short-term borrowings	1,115
Federal Home Loan Bank advances	46,828
Junior subordinated debentures	17,197
Accrued interest payable	882
Level 3 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Cash and due from banks, Federal funds sold and interest bearing deposits in other banks
Securities
Restricted stock
Portfolio loans, net	868,716
Loans held for sale	0
Accrued interest receivable	0
Demand, savings and money market
Certificates of deposit
Short-term borrowings
Federal Home Loan Bank advances
Junior subordinated debentures
Accrued interest payable