Quarterly report pursuant to Section 13 or 15(d)

Debt (Details)

v3.7.0.1
Debt (Details) - USD ($)
1 Months Ended 3 Months Ended 6 Months Ended
Jan. 31, 2015
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Long-term Debt, Fiscal Year Maturity [Abstract]            
Debt outstanding   $ 200,800,000   $ 200,800,000   $ 216,300,000
Deferred financing costs   1,400,000   $ 1,400,000   1,700,000
LIBOR            
Long-term Debt, Fiscal Year Maturity [Abstract]            
Base margin       2.25%    
Base Rate            
Long-term Debt, Fiscal Year Maturity [Abstract]            
Base margin       1.00%    
Term Loan Facility            
Long-term Debt, Fiscal Year Maturity [Abstract]            
Term loan payments 2017   11,200,000   $ 11,200,000    
Term loan payments 2018   28,100,000   28,100,000    
Term loan payments 2019   30,000,000   30,000,000    
Term loan payments 2020   36,300,000   36,300,000    
Borrowings outstanding   105,600,000   105,600,000    
Revolving Loan Facility            
Long-term Debt, Fiscal Year Maturity [Abstract]            
Revolving loans maximum borrowing capacity   150,000,000   150,000,000    
Revolving loans amount outstanding   95,200,000   95,200,000   100,400,000
Letters of credit outstanding   $ 0   0   $ 0
Amended and Restated            
Long-term Debt, Fiscal Year Maturity [Abstract]            
Revolving Loans, Potential Increment in Maximum Borrowing Capacity       $ 75,000,000    
Amortization period of debt issuance costs 5 years          
Duration of interest rate cash flow hedge   3 years        
Effective interest rate   3.60%   3.60%    
Interest expense, net   $ 1,900,000 $ 1,900,000 $ 3,800,000 $ 3,800,000  
Amended and Restated | Minimum            
Long-term Debt, Fiscal Year Maturity [Abstract]            
Interest rate range   3.42%   3.42%    
Amended and Restated | Maximum            
Long-term Debt, Fiscal Year Maturity [Abstract]            
Interest rate range   5.25%   5.25%    
Amended and Restated | Swap            
Long-term Debt, Fiscal Year Maturity [Abstract]            
Derivative notional amount   $ 85,000,000   $ 85,000,000