Long-Term Debt and Senior Subordinated Credit Facility - Schedule of Long-term Debt (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Long-term debt, including current portion	$ 505,282	$ 529,674
Current portion of long-term debt	18,488	15,066
Long-term debt	486,794	514,608
Equipment Debt [Member]
Debt Instrument [Line Items]
Long-term debt, gross	23,501	25,552
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility	0	19,000
Term Loan Facility
Debt Instrument [Line Items]
Long-term debt, gross	484,050	487,725
Discount on term loan facility	$ (2,269)	$ (2,603)