Cash and Due From Banks - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Cash And Cash Equivalents [Abstract]
Reserve Requirements	$ 10.1	$ 8.2

Cash deposited in a special reserve account for the exclusive benefit of customers pursuant to SEC Regulations.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 305

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6478312&loc=d3e61473-112792

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