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Commitments and Off-Balance Sheet Risk - Additional Information (Detail) (USD $)			9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Maximum [Member]	Sep. 30, 2013 Minimum [Member]	Sep. 30, 2013 Interest Rate Swap Agreement [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Notional amount of the underlying interest rate swap agreements entered into by commercial loan customers with correspondent banks					$ 18,100,000
Net fair value of interest rate swaps entered into by commercial loan customers with correspondent banks	(2,700,000)
Fees accreted into income during interest rate swap agreements years			15 years	4 years
Reserve or liability balance for financial instruments with off-balance sheet risk	$ 0	$ 0

X

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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- Definition

Fees accreted into income during interest rate swap agreements years.

+ References

No definition available.

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X

- Definition

Reserve or liability balance for financial instruments with off balance sheet risk.

+ References

No definition available.

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X

- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13433-108611



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13495-108611



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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

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