Variable Interest Entities (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Variable Interest Entity [Line Items]
Percentage of equity shares of each trust owned by the company	100.00%
Redemption trust preferred securities outstanding	$ 5.0
Redemption payment date	August 20, 2012
Redemption Price Percentage	104.581%
Redemption principal amount	$ 5.23

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 5A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=7880789&loc=SL6759159-111685

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration