Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt	$ 812,250	$ 836,500
Less: unamortized loan fees	12,354	14,542
Total debt, net of unamortized loan fees	799,896	821,958
Current maturities of long term debt, net of current unamortized loan fees	84,631	64,397
Long-term debt, less current maturities, net of unamortized loan fees	715,265	757,561
Term loan A-1
Debt Instrument [Line Items]
Long-term debt	412,250	436,500
Term loan A-2
Debt Instrument [Line Items]
Long-term debt	$ 400,000	$ 400,000