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Allowance for Loan Losses - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015 Contract	Mar. 31, 2014 Contract	Dec. 31, 2014
Allowance For Loan Losses [Line Items]
TDRs performing under the restructured terms	$ 1,800,000us-gaap_FinancingReceivableModificationsRecordedInvestment		$ 1,900,000us-gaap_FinancingReceivableModificationsRecordedInvestment
Loans modified under TDRs	0us-gaap_FinancingReceivableModificationsNumberOfContracts2	1us-gaap_FinancingReceivableModificationsNumberOfContracts2
Pre-modification recorded investment totaled		283,000us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Post-modification recorded investment totaled		344,000us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Troubled debt restructuring loan subsequent default	0us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Troubled debt restructuring loan subsequent default period	90 days
Performing Financing Receivable [Member]
Allowance For Loan Losses [Line Items]
TDRs performing under the restructured terms	$ 782,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_InternalCreditAssessmentAxis = us-gaap_PerformingFinancingReceivableMember		$ 790,000us-gaap_FinancingReceivableModificationsRecordedInvestment / us-gaap_InternalCreditAssessmentAxis = us-gaap_PerformingFinancingReceivableMember

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- Definition

Financing receivable modification as troubled debt restructuring that subsequently defaulted.

+ 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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Post-modification amount of investment in financing receivables 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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Pre-modification amount of investment in financing receivables 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

The amount of the outstanding recorded investment related to 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 40

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18845-111554

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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

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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