Loans and Allowance for Credit Losses - Troubled Debt Restructuring is 90 Days or More Past Due (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014 Contract	Sep. 30, 2013 Contract	Sep. 30, 2014 Contract	Sep. 30, 2013 Contract
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of Contracts			3	3
Recorded Investment			$ 18	$ 18
Number of Contracts	1	2
Recorded Investment	5	14
Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of Contracts			3	1
Recorded Investment			18	9
Number of Contracts	1	1
Recorded Investment	5	9
Loans to individuals [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of Contracts			0	2
Recorded Investment			0	9
Number of Contracts	0	1
Recorded Investment	$ 0	$ 5

Financing Receivable, Modification, Subsequent Default, Recorded Investment

No definition available.

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- Definition

Troubled debt restructuring number of contracts 90 days past due.

+ References

No definition available.

+ Details

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 34

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953682-111524

+ Details

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- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

+ Details

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- Details

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