Information Regarding Troubled Debt Restructurings (Detail) - Non-Covered Loans - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	$ 26,502	$ 45,763
Multi-Family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	5,286	25,576
Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	18,425	18,078
One-to-four family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	885	260
Acquisition, Development and Construction
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	525	654
Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	1,163	1,195
Other loan
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	218
Accruing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	8,078	15,836
Accruing | Multi-Family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	2,025	7,697
Accruing | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	6,053	8,139
Non-Accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	18,424	29,927
Non-Accrual | Multi-Family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	3,261	17,879
Non-Accrual | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	12,372	9,939
Non-Accrual | One-to-four family
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	885	260
Non-Accrual | Acquisition, Development and Construction
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	525	654
Non-Accrual | Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	1,163	$ 1,195
Non-Accrual | Other loan
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings	$ 218