Investment and Mortgage-Backed Securities, Available for Sale (Schedule of Held to Maturity Securities, Contractual Maturities) (Details) - USD ($)	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Available-for-sale Securities, Gross Realized Losses	$ 67,000	$ 162,000
Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract]
Less Than One Year, Amortized Cost	1,125,559
One – Five Years, Amortized Cost	11,035,958
Five – Ten Years, Amortized Cost	42,005,204
After Ten Years, Amortized Cost	140,697,754
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis	376,910,106
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Less Than One Year, Fair Value	1,122,015
One – Five Years, Fair Value	10,987,529
Five – Ten Years, Fair Value	41,714,850
After Ten Years, Fair Value	140,047,444
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	$ 373,752,293

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth fiscal year through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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