Annual report pursuant to Section 13 and 15(d)

Long Term Debt (Schedule of Long Term Debt) (Details)

v3.8.0.1
Long Term Debt (Schedule of Long Term Debt) (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Feb. 02, 2015
USD ($)
Debt Instrument [Line Items]      
Long-term debt, gross $ 1,415,631 $ 1,373,783  
Less unamortized discount 19,466 21,878  
Less unamortized deferred loan fees 14,117 15,133  
Less current portion of long-term debt 2,989 3,326  
Long-term debt, net $ 1,379,059 1,333,446  
Minimum      
Debt Instrument [Line Items]      
Interest coverage ratio 2.50    
Maximum      
Debt Instrument [Line Items]      
Total leverage ratio 5.95    
Senior leverage ratio 3.00    
Medium-term Notes | Senior Credit Facility | Term Loan B      
Debt Instrument [Line Items]      
Principal payments (as a percent) 0.25%    
Long-term debt, gross $ 242,583 245,187  
Medium-term Notes | Senior Credit Facility | Term Loan B | LIBOR      
Debt Instrument [Line Items]      
Basis spread on variable rate (as a percent) 2.25%    
Medium-term Notes | Senior Credit Facility | Term Loan A      
Debt Instrument [Line Items]      
Long-term debt, gross $ 215,000 215,000  
Medium-term Notes | Senior Credit Facility | Term Loan A | Minimum | LIBOR      
Debt Instrument [Line Items]      
Basis spread on variable rate (as a percent) 2.00%    
Medium-term Notes | Senior Credit Facility | Term Loan A | Maximum | LIBOR      
Debt Instrument [Line Items]      
Basis spread on variable rate (as a percent) 3.00%    
Line of Credit | Revolving Credit Facility | Maximum      
Debt Instrument [Line Items]      
Senior leverage ratio 3.00    
Line of Credit | Senior Credit Facility | Revolving Credit Facility      
Debt Instrument [Line Items]      
Long-term debt, gross $ 100,000 55,000  
Line of Credit | Senior Credit Facility | Revolving Credit Facility | Minimum | LIBOR      
Debt Instrument [Line Items]      
Basis spread on variable rate (as a percent) 2.00%    
Line of Credit | Senior Credit Facility | Revolving Credit Facility | Maximum | LIBOR      
Debt Instrument [Line Items]      
Basis spread on variable rate (as a percent) 3.00%    
Senior Notes | 2025 Notes      
Debt Instrument [Line Items]      
Stated percentage 6.875%    
Long-term debt, gross $ 450,000 450,000  
Senior Notes | 2021 Notes      
Debt Instrument [Line Items]      
Stated percentage 6.75%    
Long-term debt, gross $ 325,000 325,000  
Unsecured Debt | Searchlight Note      
Debt Instrument [Line Items]      
Stated percentage 7.50%    
Long-term debt, gross $ 75,000 75,000  
Less unamortized discount     $ 21,700
Notes Payable to Banks | Wells Fargo Note      
Debt Instrument [Line Items]      
Long-term debt, gross $ 8,048 $ 8,596  
Notes Payable to Banks | Wells Fargo Note | LIBOR      
Debt Instrument [Line Items]      
Basis spread on variable rate (as a percent) 2.25%