Quarterly report pursuant to Section 13 or 15(d)

Debt and Interest Rate Swap (Details)

v3.19.1
Debt and Interest Rate Swap (Details) - USD ($)
$ in Thousands
3 Months Ended 17 Months Ended 23 Months Ended
May 12, 2017
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 2019
Mar. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Nov. 03, 2017
Debt Instrument [Line Items]                
Debt Instrument, Unamortized Discount $ (2,100)              
Long-term debt   $ 241,044   $ 241,044 $ 241,044 $ 255,757    
Line of Credit Facility, Incremental Borrowing Capacity   $ 160,000   $ 160,000 $ 160,000      
Debt Instrument, Frequency of Periodic Payment   quarterly installments            
Debt Instrument, Quarterly Amortization Rate   0.25%   0.25% 0.25%      
Debt Instrument, Call Feature   1.0% soft call premium            
Debt Instrument, Soft Call Premium Rate   1.00%            
Repayments of Debt         $ 178,000      
Debt Instrument, Interest Rate, Effective Percentage   4.80%   4.80% 4.80% 4.60%    
Long-term Debt, Fair Value $ 398,500 $ 250,200   $ 250,200 $ 250,200 $ 268,100    
Debt Instrument, Interest Rate, Basis for Effective Rate 0.046              
Debt Issuance Costs, Gross $ 6,000              
Amortization of debt issuance costs and accretion of discount on debt and leases   402 $ 287          
Debt Instrument, Annual Principal Payment   $ 247,000   $ 247,000 $ 247,000 262,000    
Derivative, Fixed Interest Rate   4.25%   4.25% 4.25%     1.74685%
Derivative Asset   $ 1,005 2,118 $ 1,005 $ 1,005 1,623 $ 734  
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)   (618) 1,384          
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax   $ (488) $ 1,196 1,000        
Base Rate [Member]                
Debt Instrument [Line Items]                
Debt Instrument, Interest Rate Terms   a base rate            
Debt Instrument, Basis Spread on Variable Rate   1.50%            
Federal Funds Effective Swap Rate [Member]                
Debt Instrument [Line Items]                
Debt Instrument, Interest Rate Terms   the federal funds rate, plus 0.50%            
Debt Instrument, Basis Spread on Variable Rate   0.50%            
Prime Rate [Member]                
Debt Instrument [Line Items]                
Debt Instrument, Interest Rate Terms   prime rate            
One, Two, Or Three Month London Interbank Offered Rate (LIBOR) [Member]                
Debt Instrument [Line Items]                
Debt Instrument, Interest Rate Terms   an adjusted LIBOR rate determined on the basis of a one- three- or six-month interest period, plus 1.0%            
Debt Instrument, Basis Spread on Variable Rate   1.00%            
London Interbank Offered Rate (LIBOR) Subject to Floor [Member]                
Debt Instrument [Line Items]                
Debt Instrument, Interest Rate Terms   adjusted LIBOR rate, subject to a floor of 0.75%            
Debt Instrument, Basis Spread on Variable Rate   2.50%            
Debt Instrument, Variable Rate Basis Floor   0.75%            
London Interbank Offered Rate (LIBOR) [Member]                
Debt Instrument [Line Items]                
Debt Instrument, Basis Spread on Variable Rate   2.50%            
Medium-term Notes [Member]                
Debt Instrument [Line Items]                
Long-term Debt, Gross $ 425,000 $ 247,000   247,000 247,000 262,000    
Debt Instrument, Unamortized Discount   (1,555)   (1,555) (1,555) (1,630)    
Debt Issuance Costs, Net   (4,401)   (4,401) (4,401) (4,613)    
Long-term Debt   241,044   241,044 241,044 255,757    
Long-term Debt, Current Maturities   0   0 0 0    
Long-term debt   241,044   241,044 241,044 255,757    
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Derivative Financial Instruments, Assets [Member]                
Debt Instrument [Line Items]                
Derivative Asset   $ 1,005   $ 1,005 $ 1,005 $ 1,623