Investment and Mortgage-Backed Securities, Held to Maturity (Schedule of investment and mortgage-backed securities held to maturity) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, gross unrealized gains		$ 63,342
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	$ 28,424,015	25,583,956
Held to maturity, gross unrealized losses	194,328	276,246
Held-to-maturity Securities, Fair Value	28,327,987	25,371,052
Available-for-sale Securities, Gross Realized Losses	0
US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	1,997,782
Held to maturity, gross unrealized losses	5,597
Held-to-maturity Securities, Fair Value	1,992,185
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	24,426,233	25,583,956
Held to maturity, gross unrealized gains	98,300	63,342
Held to maturity, gross unrealized losses	180,953	276,246
Held-to-maturity Securities, Fair Value	$ 24,343,580	$ 25,371,052