Long-Term Debt (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Long-term debt
Long term debt	$ 340,900,000	$ 379,700,000
Less current maturities	150,000
Long term debt, net current portion	340,664,000	379,662,000
Senior Notes [Member]
Long-term debt
Long term debt	320,900,000	379,700,000
Term Loan [Member]
Long-term debt
Long term debt	$ 20,000,000	$ 0