Deposits - Additional Information (Detail) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Deposit Liabilities [Line Items]
Deposits	$ 257,071,000	$ 294,686,000
Certificates of deposit
Deposit Liabilities [Line Items]
Deposits	169,968,000	196,515,000
Amount of time deposits in denominations of 100,000 or more	121,200,000	128,100,000
Brokered Deposits
Deposit Liabilities [Line Items]
Deposits	$ 2,900,000	$ 9,200,000