Quarterly report pursuant to Section 13 or 15(d)

Debt (Details)

v3.8.0.1
Debt (Details) - USD ($)
1 Months Ended 3 Months Ended
Jan. 01, 2018
Jan. 31, 2015
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Debt Instrument [Line Items]          
Deferred financing costs     $ 2,600,000   $ 1,100,000
Long-term Debt, Fiscal Year Maturity [Abstract]          
Debt outstanding     $ 165,000,000   173,700,000
LIBOR          
Long-term Debt, Fiscal Year Maturity [Abstract]          
Base margin     1.75%    
Base Rate          
Long-term Debt, Fiscal Year Maturity [Abstract]          
Base margin     0.50%    
Term Loan Facility          
Long-term Debt, Fiscal Year Maturity [Abstract]          
Term loan payments 2018     $ 7,500,000    
Term loan payments 2019     10,000,000    
Term loan payments 2020     11,900,000    
Term loan payments 2021     14,400,000    
Term loan payments 2022     15,000,000    
Term loan payments 2023     41,200,000    
Borrowings outstanding     100,000,000    
Revolving Loan Facility          
Long-term Debt, Fiscal Year Maturity [Abstract]          
Revolving loans maximum borrowing capacity     300,000,000    
Revolving loans amount outstanding     65,000,000   79,300,000
Letters of credit outstanding     0   0
Amended and Restated          
Debt Instrument [Line Items]          
Deferred financing costs     1,700,000    
Amortization period of debt issuance costs 5 years        
Long-term Debt, Fiscal Year Maturity [Abstract]          
Revolving Loans, Potential Increment in Maximum Borrowing Capacity     $ 100,000,000    
Duration of interest rate cash flow hedge   3 years      
Effective interest rate     3.53%    
Interest expense, net     $ 1,500,000 $ 1,900,000  
Amended and Restated | Minimum          
Long-term Debt, Fiscal Year Maturity [Abstract]          
Interest rate range     3.00%    
Amended and Restated | Maximum          
Long-term Debt, Fiscal Year Maturity [Abstract]          
Interest rate range     5.25%    
Amended and Restated | Swap          
Long-term Debt, Fiscal Year Maturity [Abstract]          
Derivative notional amount     $ 50,000,000   $ 85,000,000