Covered Loans Thirty to Eighty Nine Days, Ninety Days or More Past Due (Detail) - Covered Loans - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Loans 90 Days Or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 142,176	$ 157,889
Loans 90 Days Or More Past Due | One-to-four family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	135,297	148,967
Loans 90 Days Or More Past Due | Other loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,879	8,922
Financing Receivable, 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	38,282	41,696
Financing Receivable, 30-89 Days Past Due | One-to-four family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	35,403	37,680
Financing Receivable, 30-89 Days Past Due | Other loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 2,879	$ 4,016