Investment Securities - Additional Information (Detail) (USD $)	12 Months Ended		3 Months Ended
	Dec. 31, 2013	Mar. 31, 2014 Investment	Mar. 31, 2013 Municipal obligations	Mar. 31, 2014 Government and agencies debt securities Investment
Investment [Line Items]
Number of investment positions in continuous loss position		85		83
Percentage amount by which investment positions in continuous loss position had depreciated from amortized cost basis				2.30%
Gross gains on sales of available for sale securities			$ 21,000
Number of shares acquired	100,000
Percentage of outstanding in common stock	7.00%
Total investment	$ 540,000