v3.20.4
ALLOWANCE FOR CREDIT LOSSES (Tables)
12 Months Ended
Dec. 31, 2020
Allowance for Credit Loss [Abstract]  
Allowance for Credit Losses [Table Text Block]
The balance of and changes in the allowance for credit losses consisted of the following:
 Year Ended December 31,
 202020192018
 (Thousands of Dollars)
Balance as of beginning of year$72 $9,412 $9,380 
Current period provision for credit losses441 2,322 233 
Write-offs charged against the allowance(513)(11,662)(201)
Balance as of end of year$— $72 $9,412