Other Real Estate Owned - Activity in Other Real Estate Owned (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Regulatory Assets [Abstract]
Repossessed personal property	$ 0.2us-gaap_ForeclosedAssets	$ 0.3us-gaap_ForeclosedAssets

Carrying amount as of the balance sheet date of all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings or defeasance; includes real and personal property; equity interests in corporations, partnerships, and joint ventures; and beneficial interests in trusts.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4437-111522

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