Investment and Mortgage-Backed Securities, Available for Sale (Schedule of Held to Maturity Securities, Contractual Maturities) (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)
Investments, Debt and Equity Securities [Abstract]
Available-for-sale Securities, Gross Realized Losses	$ 162,000,000	$ 162,000
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Less Than One Year, Amortized Cost	190,589	190,589
One – Five Years, Amortized Cost	14,816,156	14,816,156
Five – Ten Years, Amortized Cost	47,080,250	47,080,250
After Ten Years, Amortized Cost	142,937,006	142,937,006
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis	382,775,623	382,775,623
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Less Than One Year, Fair Value	190,501	190,501
One – Five Years, Fair Value	14,930,955	14,930,955
Five – Ten Years, Fair Value	47,638,450	47,638,450
After Ten Years, Fair Value	146,048,706	146,048,706
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	$ 388,643,233	$ 388,643,233