Summary of Significant Accounting Policies, (Details Textual)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of Significant Accounting Policies (Textual) [Abstract]
Minimum percentage at which subsidiaries consolidated (in hundredths)	50.00%
Percentage of revenue elimination (in hundredths)	71.00%	77.00%	100.00%