|**Bank Lines of Credit**                                                    | 12 Months Ended                                                                                                                                                                                              
|--------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
|**Debt Disclosure [Abstract]**                                              |                                                                                                                                                                                                              
|Bank Lines of Credit                                                        | Bank lines of creditBank lines of credit are summarized as follows:20202019Maximum borrowings available under bank lines of credit (all foreign banks)$74,766$79,930Unused bank lines of credit$74,766$79,930
|                                                                            |                                                                                                                                                                                                              
|                                                                            | 2020                                                                                                                                                                                                         
|Maximum borrowings available under bank lines of credit (all foreign banks) | $                                                                                                                                                                                                            
|                                                                            |                                                                                                                                                                                                              
|                                                                            |                                                                                                                                                                                                              
|Unused bank lines of credit                                                 | $                                                                                                                                                                                                            

X- ReferencesNo definition available.
+ Details**Name:**
us-gaap_DebtDisclosureAbstract**Namespace Prefix:**
us-gaap_**Data Type:**
xbrli:stringItemType**Balance Type:**
na**Period Type:**
duration X- DefinitionThe entire disclosure for short-term debt.
+ ReferencesReference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -URI http://asc.fasb.org/topic&trid=2208564
+ Details**Name:**
us-gaap_ShortTermDebtTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration