Investment and Mortgage-Backed Securities, Held to Maturity (Schedule of Held-to-maturity Securities) (Details)	9 Months Ended
	Sep. 30, 2017 USD ($)
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 2,887,132
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss	20,454
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	2,851
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,424,142
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	17,603
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	4,311,274
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	889,172
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss	18,414
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	811
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,424,142
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	17,603
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	$ 2,313,314