Loans and Allowance - Past Due Financing Receivables (Detail) (Loans Receivable, USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 272,664,631	$ 269,039,107	$ 246,531,094
30-89 Days Past Due	2,591,196	1,467,235	1,870,193
90 Days or More and Still Accruing	196,772	1,607,743	1,612,740
Non-accrual	2,777,904	2,713,393	4,008,665
Total	278,230,503	274,827,478	254,022,692
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,518,752	4,158,461	4,678,297
30-89 Days Past Due			205,524
90 Days or More and Still Accruing
Non-accrual		14,286	17,286
Total	3,518,752	4,172,747	4,901,107
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	64,545,207	66,191,062	68,879,791
30-89 Days Past Due	313	173,000
90 Days or More and Still Accruing		1,176,899	1,353,993
Non-accrual	1,097,112	1,237,647	2,645,320
Total	65,642,632	68,778,608	72,879,104
Consumer and indirect
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	81,315,689	71,755,109	64,427,468
30-89 Days Past Due	2,272,101	1,137,112	1,431,624
90 Days or More and Still Accruing
Non-accrual	515,352	338,212	237,193
Total	84,103,142	73,230,433	66,096,285
Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	123,284,983	126,934,475	108,545,538
30-89 Days Past Due	318,782	157,123	233,045
90 Days or More and Still Accruing	196,772	430,844	258,747
Non-accrual	1,165,440	1,123,248	1,108,866
Total	$ 124,965,977	$ 128,645,690	$ 110,146,196

Financing receivables that are less than 60 days past due but more than 29 days past due.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 7A

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953401-111524

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- Definition

Financing receivables that are current.

+ References

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- Definition

Financing receivables that are equal to or greater than 90 days past due.

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- Definition

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 7

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5111-111524

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- Definition

Recorded Investment in financing receivables that are past due at the balance sheet date.

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