LOANS - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Financing Receivable, Recorded Investment [Line Items]
Gain on business disposition	$ 9,800,000	$ 9,823,000
Gain on business disposition, after tax	5,900,000
Sales of loan held for investment in connection with business disposition	92,100,000
Total loans, net		30,152,154,000	29,041,595,000
Covered loans		3,753,031,000	4,297,869,000
Provision for losses on loans		100,420,000	102,903,000	63,000,000
FDIC indemnification income		17,633,000	11,308,000
One- to Four-Family
Financing Receivable, Recorded Investment [Line Items]
Covered loans		3,366,456,000
Financing Receivable Troubled Debt Restructurings Rate Reductions
Financing Receivable, Recorded Investment [Line Items]
Delinquent loans selectively extended to certain borrowers, rate reductions, forbearance of arrears, and extension of maturity dates		246,700,000
Financing Receivable Troubled Debt Restructurings Maturity Dates Extension
Financing Receivable, Recorded Investment [Line Items]
Delinquent loans selectively extended to certain borrowers, rate reductions, forbearance of arrears, and extension of maturity dates		246,700,000
Financing Receivable Troubled Debt Restructurings Forbearance Of Arrears
Financing Receivable, Recorded Investment [Line Items]
Delinquent loans selectively extended to certain borrowers, rate reductions, forbearance of arrears, and extension of maturity dates		40,400,000
Total non-accrual mortgage loans
Financing Receivable, Recorded Investment [Line Items]
Unpaid principal balance of serviced loan		13,100,000,000	9,500,000,000
Covered Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans 30-89 days past due		111,989,000	130,542,000
Total covered loans 90 days or more past due		347,442,000	360,827,000
Covered loan portfolio, current		3,300,000,000
Provision for losses on loans		21,420,000	11,903,000
FDIC indemnification income		17,600,000
Covered Loans | Impaired Loans
Financing Receivable, Recorded Investment [Line Items]
Covered loan		497,400,000	3,300,000,000
Covered Loans | Impaired Loans | Other
Financing Receivable, Recorded Investment [Line Items]
Covered loan		312,500,000	281,400,000
Covered Loans | Impaired Loans | One- to Four-Family
Financing Receivable, Recorded Investment [Line Items]
Covered loan		184,900,000	3,100,000,000
Am Trust Bank and Desert Hills Bank
Financing Receivable, Recorded Investment [Line Items]
Total loans, net		$ 4,500,000,000	$ 5,200,000,000