XML 93 R63.htm IDEA: XBRL DOCUMENT v3.25.0.1
Note 7. Restricted marketable securities (Details) - Restricted marketable securities - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]    
Restricted marketable securities $ 199,136 $ 198,310
Product minimum service life 25 years  
Restricted debt securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Restricted marketable securities $ 199,136 198,310
Payments to acquire restricted marketable securities 7,900  
Noncurrent restricted cash, held in trust [Member]    
Debt Securities, Available-for-sale [Line Items]    
Restricted cash and cash equivalents - noncurrent 5,000 6,200
U.S. debt [Member] | Restricted debt securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Restricted marketable securities 109,155 113,326
Foreign government obligations [Member] | Restricted debt securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Restricted marketable securities 49,024 51,229
Supranational debt [Member] | Restricted debt securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Restricted marketable securities 22,809 15,339
U.S. government obligations [Member] | Restricted debt securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Restricted marketable securities $ 18,148 $ 18,416