Repurchase Agreements - Narrative (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Disclosure of Repurchase Agreements [Abstract]
Repurchase agreements	$ 103,941,174	$ 44,325,000
Repurchase Agreements Weighted Average Borrowing Rates	0.49%	0.44%
Fair Value of securities pledged, including accrued interest receivable	109,863,000	46,788,000
Cash Held on Deposit with Repurchase Agreement Counterparties	$ 449,000	$ 57,000