Changes in Other Real Estate Owned (Detail) (Non Covered Loans, USD $) In Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	$ 17,907	$ 4,145
Additions	3,280	18,650
Disposals	1,356	3,989
Write-downs	3,518	899
Balance at end of period	16,313	17,907
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Additions	2,193	1,130
Disposals	1,052	1,674
Write-downs	177	172
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Additions	1,087	17,520
Disposals	304	2,315
Write-downs	$ 3,341	$ 727