Long-term Debt (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Long-term Debt
Debt and Capital Lease Obligations, Total	$ 1,230,493,000	$ 1,052,015,000
Less current maturities of long-term debt	(30,547,000)	(27,598,000)
Less discount on debt	(1,098,000)	(1,223,000)
Long-term debt, net of current maturities	1,198,848,000	1,023,194,000
Senior Secured Credit Facility
Long-term Debt
Debt and Capital Lease Obligations, Total	774,375,000	750,000,000
Senior Unsecured 5.875% Percent Notes
Long-term Debt
Debt and Capital Lease Obligations, Total	300,000,000	300,000,000
Debt instrument interest rate stated percentage	5.875%
Principal amount	300,000,000
Other Long Term Obligation
Long-term Debt
Debt and Capital Lease Obligations, Total	153,956,000
Capital Lease
Long-term Debt
Debt and Capital Lease Obligations, Total	$ 2,162,000	$ 2,015,000