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Debt (Additional Information) (Details)
3 Months Ended 9 Months Ended
Jun. 18, 2015
USD ($)
Sep. 30, 2017
USD ($)
Jun. 30, 2017
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2017
USD ($)
Sep. 30, 2016
USD ($)
Feb. 17, 2017
USD ($)
Dec. 31, 2016
USD ($)
Debt Instrument [Line Items]                
Debt issuance cost   $ 2,400,000     $ 2,400,000      
Amortization expense, debt issue costs   $ 100,000   $ 200,000 $ 400,000 $ 400,000    
Debt instrument, leverage ratio, maximum   2.75     2.75      
Capital lease, expiration date         2021      
Capital lease obligation   $ 5,700,000     $ 5,700,000      
Amortization expense related to the capital lease   100,000   100,000 200,000 300,000    
Capital lease accumulated depreciation   4,100,000     4,100,000     $ 3,400,000
Interest expense on capital lease   100,000   $ 100,000 100,000 $ 300,000    
Maximum                
Debt Instrument [Line Items]                
Dividends         20,000,000      
Credit Agreement                
Debt Instrument [Line Items]                
Variable rate lower range basis spread 37.50%              
Variable rate higher range basis spread 75.00%              
Line of credit, base reference rate description The base reference rate is the greater of the prime rate; federal funds effective rate (or the overnight bank funding rate, if greater) plus 50 basis points; or adjusted 1-month LIBOR plus 100 basis points.              
Amended Credit Facility                
Debt Instrument [Line Items]                
Credit agreement, agreement period (in years) 5 years              
Expansion option $ 50,000,000              
Debt issuance cost   1,400,000     1,400,000      
Amended Credit Facility | Federal Funds Effective Swap Rate                
Debt Instrument [Line Items]                
Variable rate lower range basis spread 0.50%              
Amended Credit Facility | LIBOR                
Debt Instrument [Line Items]                
Variable rate higher range basis spread 1.00%              
Amended Credit Facility | Bank Term Loan                
Debt Instrument [Line Items]                
Maximum borrowing capacity $ 55,000,000              
Amended Credit Facility | Revolving Credit Facility                
Debt Instrument [Line Items]                
Maximum borrowing capacity $ 295,000,000              
Third Amended Credit Agreement                
Debt Instrument [Line Items]                
Leverage ratio             3.25  
One-time leverage ratio maximum option             3.50  
ICR covenant limit             3.00  
Debt issuance cost   1,000,000     1,000,000      
Eurocurrency loans | Credit Agreement                
Debt Instrument [Line Items]                
Line of credit, LIBOR rate, minimum spread 137.50%              
Line of credit, LIBOR rate, maximum spread 175.00%              
Revolving Credit Facility | Third Amended Credit Agreement                
Debt Instrument [Line Items]                
Maximum borrowing capacity   450,000,000.0     450,000,000.0      
Additional borrowing capacity             $ 175,000,000  
Repayments of lines of credit   60,000,000 $ 50,000,000          
Outstanding borrowings   $ 131,200,000     $ 131,200,000      
Revolving Credit Facility | Third Amended Credit Agreement | Minimum                
Debt Instrument [Line Items]                
Unused capacity, commitment fee percentage         20.00%      
Revolving Credit Facility | Third Amended Credit Agreement | Maximum                
Debt Instrument [Line Items]                
Unused capacity, commitment fee percentage         30.00%