Quarterly report pursuant to Section 13 or 15(d)

Debt (CredAg) (Details)

v3.7.0.1
Debt (CredAg) (Details) - USD ($)
$ in Thousands
6 Months Ended
Nov. 19, 2015
Jun. 30, 2017
Debt    
Debt instrument covenant, prepayment term   90 days
Debt instrument covenant, leverage ratio   2.00%
Excess cash flow payment   $ 31,862
Estimated prepayment portion   32,206
Credit Agreement    
Debt    
Credit facility amount $ 100,000  
Amount outstanding   0
Voting equity of foreign subsidiary pledged (as a percent) 66.00%  
Non-voting equity of foreign subsidiary pledged (as a percent) 100.00%  
Letters of credit    
Debt    
Credit facility amount $ 5,000  
Term Notes    
Debt    
Amount outstanding   $ 106,138
Face amount 160,000  
Periodic payment $ 2,000  
Minimum | LIBOR    
Debt    
Spread on variable rate basis (as a percent)   1.50%
Minimum | Credit Agreement | LIBOR    
Debt    
Spread on variable rate basis (as a percent) 1.50%  
Maximum | LIBOR    
Debt    
Spread on variable rate basis (as a percent)   3.25%
Maximum | Credit Agreement | LIBOR    
Debt    
Spread on variable rate basis (as a percent) 3.25%