Covered Loans Thirty to Eighty Nine Days, Ninety Days or More Past Due (Detail) (Covered Loans, USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 90 days or more past due	$ 317,137	$ 347,442
Loans 30-89 Days Past Due	91,920	111,989
One-to-four family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 90 days or more past due	297,293	314,821
Loans 30-89 Days Past Due	84,471	103,495
Other loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 90 days or more past due	19,844	32,621
Loans 30-89 Days Past Due	$ 7,449	$ 8,494