XML 119 R105.htm IDEA: XBRL DOCUMENT v3.19.1
Financial Assets and Financial Liabilities - Additional Information (Detail) - USD ($)
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Disclosure Of Financial Instruments [Line Items]      
Dividends received $ 105,000 $ 100,000 $ 96,000
Maximum borrowing capacity 275,334,000 $ 250,923,000  
Unused portion of the credit lines $ 182,000,000    
Liquidity discount 30.00% 30.00%  
Line Of Credit 1 [Member]      
Disclosure Of Financial Instruments [Line Items]      
Unused portion of the credit lines $ 182,361,000 $ 144,478,000  
Letters of Credit [Member]      
Disclosure Of Financial Instruments [Line Items]      
Unused portion of the credit lines 92,256,000 74,911,000  
Open letters of credit [Member]      
Disclosure Of Financial Instruments [Line Items]      
Unused portion of the credit lines 22,426,000 37,559,000  
Foreign currency forward contracts [Member]      
Disclosure Of Financial Instruments [Line Items]      
Outstanding forward contracts, notional amount $ (9,400,000) $ (18,900,000)