Loans - Additional Information (Detail)	3 Months Ended	12 Months Ended
Mar. 31, 2016 USD ($) Loans	Mar. 31, 2015 Loans	Dec. 31, 2015 USD ($) Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net unamortized loan fees \| $	$ (686,000)		$ (636,000)
Percentage of comprised loan, commercial, industrial and agricultural loans	30.00%		30.00%
Percentage of comprised loan, commercial mortgage loans	29.00%		28.00%
Percentage of loan-to-value to business equipment	80.00%
Percentage of loan-to-value to accounts receivable	75.00%
Percentage of loan-to-value to business inventory	60.00%
Percentage of loan-to-value to real estate	85.00%
Percentage of residential real estate loan in portfolio	36.00%		36.00%
Number of Loans \| Loans	16		16
Minimum period to be considered for loan to have defaulted	90 days
Principal balances forgiven in connection with loan restructuring \| $	$ 0		$ 0
Outstanding balance of semi annual loans	Greater than $1 million
Outstanding balance of annual loans	Less than $1 million
Trouble Debt Restructuring [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans \| Loans	0	0
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum percentage of consumer loan and credit card in portfolio	10.00%		10.00%

Commercial industrial and agricultural loan amount as maximum percentage of accounts receivable.

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- Definition

Commercial industrial and agricultural loan amount as maximum percentage of business equipment.

+ References

No definition available.

+ Details

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- Definition

Commercial industrial and agricultural loan amount as maximum percentage of business inventory.

+ References

No definition available.

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- Definition

Commercial mortgage loan amount as maximum percentage of appraised real estate value.

+ References

No definition available.

+ Details

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- Definition

Minimum period to be considered for loan to have defaulted.

+ References

No definition available.

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- Definition

Outstanding balance of annual loans.

+ References

No definition available.

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- Definition

Outstanding balance of semi annual loans.

+ References

No definition available.

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- Definition

Percentage of commercial industrial and agricultural loans in loan portfolio.

+ References

No definition available.

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- Definition

Percentage of commercial mortgage loans in loan portfolio.

+ References

No definition available.

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- Definition

Percentage of consumer loans and credit card products in loan portfolio.

+ References

No definition available.

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- Definition

Percentage of residential real estate loans in loan portfolio.

+ References

No definition available.

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- Definition

Troubled debt restructuring loan principal balance forgiven.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ 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=49124121&loc=SL6953676-111524

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- Definition

Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10092-111533

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