Investment and Mortgage-Backed Securities, Held to Maturity (Narrative) (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Investments, Debt and Equity Securities [Abstract]
Held-to-maturity Securities Pledged as Collateral	$ 13,800,000	$ 12,200,000
Held to Maturity Securities Pledged as Collateral, Fair Value	14,400,000	12,800,000
Schedule of Held-to-maturity Securities [Line Items]
Held To Maturity, Amortized Cost	74,196,803	76,072,262
Held-to-maturity Securities, Fair Value	77,376,402	79,671,886
GNMA Mortgage-Backed Securities
Schedule of Held-to-maturity Securities [Line Items]
Held To Maturity, Amortized Cost	46,900,000	47,200,000
Held-to-maturity Securities, Fair Value	$ 49,700,000	$ 50,400,000