Commitments and Contingent Liabilities - Additional Information (Detail) (USD $)					9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Unused commitments and letters of credit [Member]	Dec. 31, 2012 Unused commitments and letters of credit [Member]	Sep. 30, 2013 Pending Litigation [Member] Accountsholder	Sep. 30, 2013 Pending Litigation [Member] IRA Market Rate Savings Account [Member]	Sep. 30, 2013 Pending Litigation [Member] IRA Market Rate Savings Account [Member] Minimum [Member]	Sep. 30, 2013 Other Matters [Member]	Sep. 30, 2013 Other Matters [Member] Minimum [Member] customer	Sep. 30, 2013 Other Matters [Member] Maximum [Member] customer
Loss Contingencies [Line Items]
Specified Average Age Of Account Holders					64 years
Notional amount of financial standby letters of credit	$ 737,000
Notional amount of performance standby letters of credit	1,200,000
Notional amount of commercial letters of credit	0
Financial instrument of credit risk	100,000	200,000
Unfunded commitment liability			2,600,000	2,400,000
Percentage of interest rate on deposits						3.50%	8.00%
Number of account holders of specified average age					237
Savings deposits					11,500,000
Number of customers affected (in customers)									700	900
Contingency reserve								$ 800,000