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	6 Months Ended
	Jun. 30, 2014	Jun. 30, 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	2	8
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments	0	4
Gross Gains	2	4
Gross Losses	0	0
Gain Losses Maturities And Impairment	$ 2	$ 4