Securities - Amortized cost and approximate fair values, together with gross unrealized gains and losses, of securities (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, amortized cost	$ 101,943,704	$ 86,275,846
Available-for-sale securities, gross unrealized gains	638,929	1,563,287
Available-for-sale securities, gross unrealized losses	(2,421,193)	(365,801)
Available-for-sale securities, fair value	100,161,440	87,473,332
U.S. Government and federal agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, amortized cost	13,985,863	15,979,475
Available-for-sale securities, gross unrealized gains	9,641	44,972
Available-for-sale securities, gross unrealized losses	(661,964)	(85,750)
Available-for-sale securities, fair value	13,333,540	15,938,697
Mortgage-backed securities (Government-sponsored enterprises - residential)
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, amortized cost	45,457,262	23,067,200
Available-for-sale securities, gross unrealized gains	70,512	211,987
Available-for-sale securities, gross unrealized losses	(1,114,597)	(100,792)
Available-for-sale securities, fair value	44,413,177	23,178,395
Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, amortized cost	42,500,579	47,229,171
Available-for-sale securities, gross unrealized gains	558,776	1,306,328
Available-for-sale securities, gross unrealized losses	(644,632)	(179,259)
Available-for-sale securities, fair value	$ 42,414,723	$ 48,356,240

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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