Debt Obligations (Narrative) (Details) (USD $)	12 Months Ended				12 Months Ended					12 Months Ended			12 Months Ended
	Dec. 31, 2012	Mar. 11, 2013	Nov. 08, 2012	Dec. 31, 2011	Dec. 31, 2012 Provident Bank [Member]	Mar. 11, 2013 Maximum [Member]	Nov. 08, 2012 Maximum [Member]	Mar. 11, 2013 Minimum [Member]	Nov. 08, 2012 Minimum [Member]	Dec. 31, 2012 CoBank ACB, Unsecured Term Credit Facility [Member]	Dec. 31, 2011 CoBank ACB, Unsecured Term Credit Facility [Member]	Dec. 31, 2010 CoBank ACB, Unsecured Term Credit Facility [Member]	Dec. 31, 2011 CoBank ACB Revolving Loan Facility [Member]	Dec. 31, 2012 CoBank ACB Revolving Loan Facility [Member]	Aug. 02, 2012 CoBank ACB Revolving Loan Facility [Member]
Line of Credit Facility [Line Items]
Unsecured term credit facility										$ 18,500,000
Long-term debt (current maturities)				1,139,000							1,139,000
Interest rate on borrowing										2.94%	2.98%	2.96%		4.71%
Credit facilty, borrowing capacity			2,500,000										5,000,000		10,000,000
Interest rate percent, plus LIBOR						3.50%	4.00%	2.00%	3.00%						4.50%
Interest rate percent on outstanding revolving loan facility													3.50%
Line of credit, drawdown					4,000,000
Fixed interest rate percent					2.50%
Consolidated leverage ratio	250.00%
Line of credit facility, maximum						20,000,000		17,000,000
Line of credit facility, outstanding		$ 15,200,000