Changes in Covered Other Real Estate Owned (Detail) (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	$ 35,257	$ 12,916
Additions	23,557	32,064
Disposals	17,591	9,280
Write-downs	4,536	443
Balance at end of period	36,687	35,257
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Additions	1,825	9,827
Disposals	6,091	4,536
Write-downs	1,012	29
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Additions	21,732	22,237
Disposals	11,500	4,744
Write-downs	$ 3,524	$ 414