Annual report pursuant to Section 13 and 15(d)

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

v3.10.0.1
Short-Term Borrowings and Credit Lines (Narrative) (Details) - 12 months ended Dec. 31, 2018
USD ($)
EUR (€)
JPY (¥)
CAD ($)
Line of Credit Facility [Line Items]        
Available credit amount $ 100,000,000      
Canadian Subsidiary [Member] | Unsecured And Uncommitted Line Of Credit [Member]        
Line of Credit Facility [Line Items]        
Interest rate description Canadian prime rate      
Maximum borrowing capacity $ 22,000,000     $ 30,000,000
European Subsidiary [Member] | Unsecured And Uncommitted Line Of Credit [Member]        
Line of Credit Facility [Line Items]        
Maximum borrowing capacity 35,000,000      
European Subsidiary [Member] | Unsecured And Uncommitted Credit Line1 [Member]        
Line of Credit Facility [Line Items]        
Maximum borrowing capacity | €   € 25,800,000    
European Subsidiary [Member] | Unsecured And Uncommitted Credit Line2 [Member]        
Line of Credit Facility [Line Items]        
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 10,000,000      
Japanese Subsidiary [Member] | Unsecured And Uncommitted Credit Line1 [Member]        
Line of Credit Facility [Line Items]        
Maximum borrowing capacity $ 7,000,000      
Japanese Subsidiary [Member] | Unsecured And Uncommitted Credit Line2 [Member]        
Line of Credit Facility [Line Items]        
Maximum borrowing capacity | ¥     ¥ 300,000,000  
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      
China Subsidiary [Member] | Unsecured And Uncommitted Line Of Credit [Member]        
Line of Credit Facility [Line Items]        
Maximum borrowing capacity $ 20,000,000      
China Subsidiary [Member] | Unsecured And Uncommitted Credit Line1 [Member]        
Line of Credit Facility [Line Items]        
Maximum borrowing capacity | €   € 137,570,000    
Committed Portion Of Credit Facility [Member] | Domestic [Member]        
Line of Credit Facility [Line Items]        
Maturity date of agreement Jul. 01, 2021