Fair Value - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value Disclosures [Abstract]
Credit spreads on Moody's rating			45 to 75 basis points
Liquidity risk adjustments ranged			20 to 55 basis points
Liquidity risk adjustments ranged, securities of 15 largest banks			20 to 40 basis points
Investment in three largest banks	$ 18,100,000		$ 18,100,000
Investment in three largest banks percentage			49.30%
Investment in Floating rate trust preferred securities			36,800,000
Write-downs on REO properties	$ 6,000	$ 7,000	$ 56,000	$ 368,000