Quality of Non-Covered Loans (Excluding PCI Loans) (Parenthetical) (Detail) (Non-Covered Loans, USD $) In Thousands, unless otherwise specified	Mar. 31, 2015
Non-Covered Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 90 days or more past due	$ 2,900

Financing receivables that are equal to or greater than 90 days past due.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 7A

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953401-111524

Name:	us-gaap_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant