Loans - Impaired Loans Classified as Troubled Debt Restructured (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014 Contract	Dec. 31, 2013 Contract
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts Modified, Troubled Debt Restructurings	0	0
Pre- Modification Outstanding Recorded Investment	$ 0	$ 0
Post- Modification Outstanding Recorded Investment	0	0
Number of Contracts Modified, Troubled Debt Restructurings That Subsequently Defaulted	0	0
Recorded Investment	0	0
Agricultural Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts Modified, Troubled Debt Restructurings	0	0
Pre- Modification Outstanding Recorded Investment	0	0
Post- Modification Outstanding Recorded Investment	0	0
Number of Contracts Modified, Troubled Debt Restructurings That Subsequently Defaulted	0	0
Recorded Investment	0	0
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts Modified, Troubled Debt Restructurings	0	0
Pre- Modification Outstanding Recorded Investment	0	0
Post- Modification Outstanding Recorded Investment	0	0
Number of Contracts Modified, Troubled Debt Restructurings That Subsequently Defaulted	0	0
Recorded Investment	$ 0	$ 0

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- Definition

Financing receivable modifications pre modification recorded investment one.

+ References

No definition available.

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953676-111524

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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=35738203&loc=SL6953682-111524

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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

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