Quarterly report pursuant to Section 13 or 15(d)

Senior Credit Facility (Details)

v3.7.0.1
Senior Credit Facility (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Mar. 31, 2015
Feb. 04, 2015
Debt Instrument [Line Items]        
Line of Credit Facility Term, In Years       5
Credit facility amount       $ 275,000
Base reference rate of credit facilities LIBOR      
Interest rate spread above LIBOR as of reporting period (in hundredths) 1.00%      
Proceeds from senior credit facility $ 13,000 $ 0    
Letters of Credit Outstanding, Amount 7,514      
Available borrowing capacity 129,486      
Letter of Credit [Member]        
Debt Instrument [Line Items]        
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases       25,000
Swing line loan [Member]        
Debt Instrument [Line Items]        
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases       15,000
Revolving Credit Facility [Member]        
Debt Instrument [Line Items]        
Credit facility amount       $ 150,000
Debt Instrument, Basis Spread on Variable Rate, Minimum       0.30%
Debt Instrument, Basis Spread on Variable Rate, Maximum       0.80%
Proceeds from senior credit facility $ 13,000      
Line of Credit Facility, Interest Rate at Period End 2.20%      
Federal funds [Member]        
Debt Instrument [Line Items]        
Interest rate spread above LIBOR as of reporting period (in hundredths) 0.50%      
Term loan [Member]        
Debt Instrument [Line Items]        
Credit facility amount       $ 125,000
Debt Instrument, Basis Spread on Variable Rate, Minimum       0.10%
Debt Instrument, Basis Spread on Variable Rate, Maximum       0.60%
Proceeds from term loan     $ 125,000  
Term Loan, Quarterly Payment Percentage 11.10%