Debt (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Maturity of Long-Term Debt
2013	$ 268,000
2014	290,000
2015	314,000
2016	340,000
2017	368,000
Thereafter	826,000
Total long-term debt	2,406,000
Less current portion	268,000	248,000
Long-term debt, net of current portion	2,138,000	2,406,000
Mortgage Payable
Debt
Land and buildings	4,800,000	5,000,000
Principal balance	2,400,000	2,700,000
Annual interest rate accrued on mortgage (as a percent)	7.91%	7.91%
Fair value of debt instrument	$ 2,600,000	$ 2,900,000