Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commitments And Contingencies Disclosure [Abstract]
Allowance for unfunded commitments	$ 2.9	$ 3.0
Data processing and communication charges	9.5	10.3	7.4
Data processing contract termination and conversion cost expenses	$ 0.8	$ 2.3

The amount of expense in the period for communications and data processing expense.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.4)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Name:	us-gaap_CommunicationsAndInformationTechnology
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration