Loans, Allowance for Loan Losses, and Credit Quality Indicators - Summary of Loan Classifications (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	$ 871,257	$ 820,829
Deferred loan origination fees	(841)	(677)
Gross loans, net of deferred income	870,416	820,152
Allowance for loan losses	(16,345)	(14,941)
Total loans, net of allowance for loan losses and net deferred fees	854,071	805,211
Loans held-for-sale		1,058
Percentage of gross loans	100.00%	100.00%
Commercial loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	325,604	272,600
Percentage of gross loans	37.40%	33.20%
Consumer loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	3,581	4,569
Percentage of gross loans	0.40%	0.60%
Other loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	1,112	1,556
Percentage of gross loans	0.10%	0.20%
Real estate loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	461,240	478,466
Real estate loans [Member] \| Multi-family residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	45,212	51,897
Real estate loans [Member] \| Residential 1-4 family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	51,437	61,717
Real estate loans [Member] \| Owner-occupied commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	219,276	207,008
Real estate loans [Member] \| Nonowner-occupied commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	145,315	157,844
Real estate secured loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	540,960	542,104
Percentage of gross loans	62.10%	66.00%
Real estate secured loans [Member] \| Real estate loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	461,240	478,466
Percentage of gross loans	53.00%	58.30%
Real estate secured loans [Member] \| Real estate loans [Member] \| Multi-family residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	45,212	51,897
Percentage of gross loans	5.20%	6.30%
Real estate secured loans [Member] \| Real estate loans [Member] \| Residential 1-4 family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	51,437	61,717
Percentage of gross loans	5.90%	7.50%
Real estate secured loans [Member] \| Real estate loans [Member] \| Owner-occupied commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	219,276	207,008
Percentage of gross loans	25.20%	25.20%
Real estate secured loans [Member] \| Real estate loans [Member] \| Nonowner-occupied commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	145,315	157,844
Percentage of gross loans	16.70%	19.30%
Real estate secured loans [Member] \| Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	79,720	63,638
Percentage of gross loans	9.10%	7.80%
Real estate secured loans [Member] \| Construction Loans [Member] \| Multi-family residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	17,022	2,574
Percentage of gross loans	2.00%	0.30%
Real estate secured loans [Member] \| Construction Loans [Member] \| Residential 1-4 family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	20,390	17,960
Percentage of gross loans	2.30%	2.20%
Real estate secured loans [Member] \| Construction Loans [Member] \| Aged Analysis of Loans Receivable [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	23,235	10,901
Percentage of gross loans	2.70%	1.30%
Real estate secured loans [Member] \| Construction Loans [Member] \| Commercial bare land and acquisition & development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	10,668	19,496
Percentage of gross loans	1.20%	2.40%
Real estate secured loans [Member] \| Construction Loans [Member] \| Residential bare land and acquisition & development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Gross loans	$ 8,405	$ 12,707
Percentage of gross loans	0.90%	1.60%

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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+ Details

- Definition

Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References+ Details

- Definition

Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References+ Details

- Definition

The aggregate carrying amount of loans receivable that will be sold to other entities. Includes mortgage and all other loans (collectively, loans) not classified as held for investment. Such loans are stated at the lower of cost or market, or elected fair value. Mortgage loans exclude mortgage-backed securities which are considered a debt security (other loan).

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