Debt - Schedule of Outstanding Debt Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total long-term debt	$ 986,521	$ 991,918
Less: current maturities	21,166	17,500
Long-term debt, net of current maturities	965,355	974,418
2023 Senior Notes
Debt Instrument [Line Items]
Total long-term debt	489,612	488,481
2015 Term Loan Facility
Debt Instrument [Line Items]
Total long-term debt	317,546	332,688
2.5% Convertible Notes
Debt Instrument [Line Items]
Total long-term debt	$ 179,363	$ 170,749