Securities (Proceeds from the sales of Available-for-Sale Securities) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Schedule of Investments [Line Items]
Proceeds from Sales and Calls			$ 100,721	$ 51,395
Gross Gains on Sales and Calls	467	76	1,080	94
Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Proceeds from Sales and Calls	25,972	9,247	100,721	51,395
Gross Gains on Sales and Calls	467	76	1,080	94
Income Taxes on Gross Gains	$ 163	$ 27	$ 378	$ 33