Information Regarding Troubled Debt Restructurings (Detail) (Non-Covered Loans, USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	$ 82,207	$ 260,306
Multi-Family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	61,336	180,648
Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	18,565	76,584
Acquisition, Development and Construction
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	1,058	510
Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	1,248	1,463
One-to-four family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings		1,101
Accruing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	14,022	105,012
Accruing | Multi-Family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	10,558	66,092
Accruing | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	2,216	37,457
Accruing | Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	1,248	1,463
Non-Accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	68,185	155,294
Non-Accrual | Multi-Family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	50,778	114,556
Non-Accrual | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	16,349	39,127
Non-Accrual | Acquisition, Development and Construction
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	1,058	510
Non-Accrual | One-to-four family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings		$ 1,101