Long-term Debt (Details) (USD $)			12 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2011 Notes payable, JPMorgan Chase N.A.	Dec. 15, 2008 Notes payable, JPMorgan Chase N.A.	Dec. 31, 2012 Notes payable, Federal Home Loan Bank of Chicago	Dec. 31, 2011 Notes payable, Federal Home Loan Bank of Chicago
Long-term Debt
Long-term debt	$ 7,000,000	$ 19,417,000	$ 417,000		$ 7,000,000	$ 19,000,000
Principal balance				2,085,000
Base rate			LIBOR
Interest rate margin (as a percent)			1.15%
Effective interest rate (as a percent)			1.45%
Annual payments				$ 417,000
Interest rate, minimum (as a percent)					4.68%
Interest rate, maximum (as a percent)					5.39%
Weighted average rate (as a percent)					5.29%	4.68%