Investment in Available-for-Sale Securities (Details) - USD ($)	6 Months Ended	12 Months Ended
Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Cost	$ 2,174,368	$ 1,925,012
Available-for-sale Securities, Gross Unrealized Gains	23,463	23,733
Available-for-sale Securities, Gross Unrealized Losses	(16,849)	(15,944)
Available-for-sale Securities, Fair Value	2,180,982	1,932,801
U.S. federal agency securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Cost	49,783	49,739
Available-for-sale Securities, Gross Unrealized Gains	90	68
Available-for-sale Securities, Gross Unrealized Losses	(23)	(117)
Available-for-sale Securities, Fair Value	49,850	49,690
Municipal securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Cost	636,997	441,372
Available-for-sale Securities, Gross Unrealized Gains	756	463
Available-for-sale Securities, Gross Unrealized Losses	(2,444)	(966)
Available-for-sale Securities, Fair Value	635,309	440,869
Certificates of deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Cost	1,470,167	1,395,990
Available-for-sale Securities, Gross Unrealized Gains	22,263	22,904
Available-for-sale Securities, Gross Unrealized Losses	(14,382)	(14,861)
Available-for-sale Securities, Fair Value	1,478,048	1,404,033
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Cost	17,421	37,911
Available-for-sale Securities, Gross Unrealized Gains	354	298
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Fair Value	$ 17,775	$ 38,209

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=51813488&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=27724398&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=49167202&loc=d3e26610-111562

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+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

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Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

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Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

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-Section 50

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