Annual report pursuant to Section 13 and 15(d)

Short-Term Borrowings and Credit Lines (Narrative) (Details)

v3.6.0.2
Short-Term Borrowings and Credit Lines (Narrative) (Details)
 12 Months Ended
Dec. 31, 2016
EUR (€)
Dec. 31, 2016
USD ($)
Dec. 31, 2016
JPY (¥)
Dec. 31, 2016
CAD
Dec. 31, 2015
USD ($)
Line of Credit Facility [Line Items]          
Available credit amount   $ 125,000,000      
Long-term Line of Credit   0     $ 1,940,000
Domestic [Member] | Unsecured And Uncommitted Line Of Credit [Member]          
Line of Credit Facility [Line Items]          
Long-term Line of Credit   0     0
Canadian Subsidiary [Member] | Unsecured And Uncommitted Line Of Credit [Member]          
Line of Credit Facility [Line Items]          
Interest rate description Canadian prime rate        
Proceeds from Lines of Credit         1,940,000
Maximum borrowing capacity   22,320,000   CAD 30,000,000  
Long-term Line of Credit   0      
European Subsidiary [Member]          
Line of Credit Facility [Line Items]          
Long-term Line of Credit   0     0
European Subsidiary [Member] | Unsecured And Uncommitted Line Of Credit [Member]          
Line of Credit Facility [Line Items]          
Maximum borrowing capacity   32,392,000      
European Subsidiary [Member] | European Customs Guaranteed Line Of Credit [Member]          
Line of Credit Facility [Line Items]          
Maximum borrowing capacity   2,419,000      
European Subsidiary [Member] | Unsecured And Uncommitted Credit Line1 [Member]          
Line of Credit Facility [Line Items]          
Interest rate description European Central Bank ("ECB") refinancing rate plus 50 basis points        
Maximum borrowing capacity | € € 25,800,000        
European Subsidiary [Member] | Unsecured And Uncommitted Credit Line2 [Member]          
Line of Credit Facility [Line Items]          
Interest rate description Euro Overnight Index Average ("EONIA") plus 75 basis points        
Maximum borrowing capacity | € € 5,000,000        
Japanese Subsidiary [Member] | Unsecured And Uncommitted Line Of Credit [Member]          
Line of Credit Facility [Line Items]          
Maximum borrowing capacity   9,565,000      
Japanese Subsidiary [Member] | Unsecured And Uncommitted Credit Line1 [Member]          
Line of Credit Facility [Line Items]          
Interest rate description JPY LIBOR plus 100 basis points        
Maximum borrowing capacity   7,000,000      
Japanese Subsidiary [Member] | Unsecured And Uncommitted Credit Line2 [Member]          
Line of Credit Facility [Line Items]          
Interest rate description Bank of Tokyo Prime Rate        
Maximum borrowing capacity | ¥     ¥ 300,000,000    
Japanese Subsidiary [Member] | Revolving Line Of Credit [Member]          
Line of Credit Facility [Line Items]          
Long-term Line of Credit   0     0
Korean Subsidiary [Member]          
Line of Credit Facility [Line Items]          
Long-term Line of Credit   0     $ 0
Korean Subsidiary [Member] | Unsecured And Uncommitted Line Of Credit [Member]          
Line of Credit Facility [Line Items]          
Interest rate description CD rate plus 220 basis points        
Maximum borrowing capacity   $ 20,000,000      
Committed Portion Of Credit Facility [Member] | Domestic [Member]          
Line of Credit Facility [Line Items]          
Maturity date of agreement Jul. 01, 2020        
Minimum [Member] | Domestic [Member] | Committed Line Of Credit [Member]          
Line of Credit Facility [Line Items]          
Interest rate description USD LIBOR plus 87.5 basis points        
Maximum [Member] | Domestic [Member] | Committed Line Of Credit [Member]          
Line of Credit Facility [Line Items]          
Interest rate description USD LIBOR plus 162.5 basis points