Other Real Estate Owned Activity (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Real Estate Properties [Line Items]
Balance at the beginning of the year			$ 57,387	$ 82,419
Loan foreclosures			8,546	12,883
Property sold			(8,719)	(3,232)
Losses on sale and write-downs	(3,464)	(1,461)	(3,464)	(2,187)
Balance at the end of the period	$ 53,750	$ 89,883	$ 53,750	$ 89,883