Significant Accounting Policies - Cash and Cash Equivalents (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Significant Accounting Policies [Abstract]
Cash Held by Borker as Margin on Eurodollar Futures Contracts	$ 0	$ 34,000
Cash Held on Deposit with Repurchase Agreement Counterparties	$ 449,000	$ 57,000
Commentary - Cash and Cash Equivalents Balances That Are Insured by the FDIC	The Company maintains cash balances at two banks, and, at times, balances may exceed federally insured limits. The Company has not experienced any losses related to these balances. All non-interest bearing cash balances were fully insured at December 31, 2012 and 2011 due to a temporary federal program in effect from December 31, 2010 through December 31, 2012. Under the program, there is no limit to the amount of insurance for eligible accounts. Beginning in 2013, insurance coverage will revert to $250,000 per depositor at each financial institution, and our non-interest bearing cash balances may again exceed federally insured limits.