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Long-Term Debt - Narrative (Details)
9 Months Ended 12 Months Ended
Oct. 04, 2018
USD ($)
Sep. 30, 2018
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
May 30, 2017
USD ($)
Debt Instrument [Line Items]            
Line of credit facility, leverage ratio 3.0 2.75        
Long-term line of credit     $ 295,000,000      
Letters of credit outstanding, amount     $ 6,200,000 $ 10,100,000    
Total debt ratio threshold     2.25      
Loss on extinguishment of debt     $ 0 14,114,000 $ 0  
Senior notes 2024            
Debt Instrument [Line Items]            
Interest rate           5.375%
Face Amount           $ 300,000,000.0
Senior notes 2021            
Debt Instrument [Line Items]            
Interest rate           6.75%
Face Amount           $ 200,000,000
Line of Credit            
Debt Instrument [Line Items]            
Maximum borrowing capacity $ 425,000,000 $ 400,000,000.0        
Long-term line of credit     295,000,000 $ 107,000,000    
Letters of credit outstanding, amount     3,200,000      
Remaining borrowing capacity     $ 126,800,000      
Commitment fee percentage     0.50%      
Interest rate at period end     4.94%      
Repayments of debt     $ 188,000,000      
Line of Credit | LIBOR            
Debt Instrument [Line Items]            
Basis spread on variable rate     2.50%      
Line of Credit | Prime Rate            
Debt Instrument [Line Items]            
Basis spread on variable rate     1.50%      
Minimum | LIBOR            
Debt Instrument [Line Items]            
Interest rate     0.00%      
Geographic Distribution, Domestic            
Debt Instrument [Line Items]            
Line of credit facility, leverage ratio 4.0 3.5