Annual report pursuant to Section 13 and 15(d)

Long-Term Debt - Summary of Long-Term Debt (Details)

v3.10.0.1
Long-Term Debt - Summary of Long-Term Debt (Details) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Oct. 11, 2017
Dec. 21, 2016
Oct. 14, 2016
Apr. 21, 2015
Debt Instrument [Line Items]            
Net unamortized debt issuance costs $ (30,733) $ (34,781)        
Less: current maturities of long term debt (651) (622)        
Debt reflected as long term 2,086,765 2,038,321        
Revolving credit agreement            
Debt Instrument [Line Items]            
Long-tern debt   0        
Senior notes | 6.625% Senior Notes Due 2023            
Debt Instrument [Line Items]            
Long-tern debt 350,000 $ 350,000        
Net unamortized debt issuance costs $ (4,400)          
Stated interest rate 6.625% 6.625%       6.625%
Senior notes | 6.000% Senior Notes Due 2024            
Debt Instrument [Line Items]            
Long-tern debt $ 650,000 $ 650,000        
Net unamortized debt issuance costs $ (8,700)          
Stated interest rate 6.00% 6.00%     6.00%  
Senior notes | 6.375% Senior Notes Due 2025            
Debt Instrument [Line Items]            
Long-tern debt $ 600,000 $ 600,000        
Net unamortized debt issuance costs $ (12,500)          
Stated interest rate 6.375% 6.375%   6.375%    
Senior notes | 6.375% Senior Notes Due 2026            
Debt Instrument [Line Items]            
Long-tern debt $ 450,000 $ 450,000        
Net unamortized debt issuance costs $ (5,000)          
Stated interest rate 6.375% 6.375% 6.375%      
Construction loans            
Debt Instrument [Line Items]            
Long-tern debt $ 23,149 $ 23,724