Income Taxes (Details 3) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Income taxes
Alternative minimum tax credit	$ 542,000	$ 527,000
Additional tax benefits reflected in net operating tax loss carryforwards persuant to SFAS 123R	2,200,000
Tax effects of windfalls included in net operating loss carryforwards	800,000
Federal
Income taxes
Operating loss carryforwards	91,100,000
Alternative minimum tax credit	500,000
State
Income taxes
Operating loss carryforwards	$ 18,300,000