Additional Information Regarding TDRs (Detail) (Non-Covered Loans, USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	$ 287,109	$ 357,471
Multi-Family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	226,702	272,173
Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	42,443	60,731
Acquisition, Development and Construction
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	15,886	17,666
Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	667	5,381
One to Four Family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	1,411	1,520
Accruing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	63,843	152,655
Accruing | Multi-Family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	60,454	148,738
Accruing | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	3,389	3,917
Non-Accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	223,266	204,816
Non-Accrual | Multi-Family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	166,248	123,435
Non-Accrual | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	39,054	56,814
Non-Accrual | Acquisition, Development and Construction
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	15,886	17,666
Non-Accrual | Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	667	5,381
Non-Accrual | One to Four Family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	$ 1,411	$ 1,520