Investment Securities - Proceeds from Sale, Gross Gains (Losses) Realized on Sales, Maturities and Other-Than-Temporary Impairment Charges Related to Securities Available for Sale (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Proceeds from sales	$ 0	$ 42
Sales Transactions:
Gross gains	0	4
Gross losses	0	0
Maturities and impairment
Net gains and impairment	$ 0	$ 4