Investment and Mortgage-Backed Securities, Held to Maturity (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Proceeds from Sale of Held-to-maturity Securities	$ 0
Held-to-maturity Securities, Fair Value	23,842,005	$ 27,054,934
Held-to-maturity Securities Pledged as Collateral	22,400,000	22,300,000
Held to maturity pledged as collateral, fair value	22,000,000
US Government Agencies Debt Securities [Member]
Held-to-maturity Securities, Fair Value	15,200,000	15,900,000
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	$ 15,500,000	$ 15,900,000