Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements (Details)

v3.6.0.2
Fair Value Measurements (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Nov. 19, 2015
Dec. 15, 2014
Fair Value Measurements        
Convertible Debt, Noncurrent $ 152,575 $ 146,418    
Term Notes 100,409 138,335    
Level 1 | Recurring Basis        
Assets        
Total Assets 31,644      
Liabilities        
Total liabilities 2,885      
Level 1 | Recurring Basis | Deferred compensation liability        
Liabilities        
Total liabilities 2,885      
Level 1 | Recurring Basis | Money market funds        
Assets        
Total Assets 31,644 24,422    
Level 2 | Recurring Basis        
Liabilities        
Total liabilities   140    
Level 2 | Recurring Basis | Foreign currency forward contracts        
Liabilities        
Total liabilities   140    
Level 3 | Recurring Basis        
Assets        
Total Assets 2,738      
Liabilities        
Total liabilities 4,868 4,043    
Level 3 | Recurring Basis | Contingent consideration        
Liabilities        
Total liabilities 4,868 4,043    
Level 3 | Recurring Basis | Deferred compensation asset        
Assets        
Total Assets 2,738      
Liabilities        
Assets Fair value Disclosure Before Adjustments 2,672      
Fair Value | Recurring Basis        
Assets        
Total Assets 34,382      
Liabilities        
Total liabilities 7,753 4,183    
Fair Value | Recurring Basis | Contingent consideration        
Liabilities        
Total liabilities 4,868 4,043    
Fair Value | Recurring Basis | Deferred compensation liability        
Liabilities        
Total liabilities 2,885      
Fair Value | Recurring Basis | Foreign currency forward contracts        
Liabilities        
Total liabilities   140    
Fair Value | Recurring Basis | Money market funds        
Assets        
Total Assets 31,644 24,422    
Fair Value | Recurring Basis | Deferred compensation asset        
Assets        
Total Assets 2,738      
Liabilities        
Gain based upon cash surrender value of life insurance 66      
Fair Value | Recurring Basis | Deferred compensation asset | General and administration        
Liabilities        
Gain based upon cash surrender value of life insurance 66      
Convertible Notes        
Fair Value Measurements        
Convertible Debt, Noncurrent 152,575 146,418    
Liabilities        
Total liabilities 164,824 152,878    
Face amount 172,500 172,500   $ 172,500
Convertible Notes | Carrying Value        
Fair Value Measurements        
Convertible Debt, Noncurrent 152,575 146,418    
Term Notes        
Fair Value Measurements        
Term Notes 138,335 144,399    
Liabilities        
Face amount $ 142,000 $ 150,000 $ 160,000