XML 26 R16.htm IDEA: XBRL DOCUMENT v3.21.2
Note 4 - Inventories (Tables)
9 Months Ended
Sep. 30, 2021
Notes Tables  
Schedule of Inventory, Current [Table Text Block]
  

September 30,

2021

  

December 31,

2020

 

Parts inventory

 $100,612  $92,481 

Fuel inventory

  117,182   59,336 

Other inventory

  15,190   11,802 

Total inventory

 $232,984  $163,619