BALANCE SHEETS (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Nuclear fuel; fuel in process	$ 57,315	$ 51,854
Allowance for Doubtful Accounts Receivable, Current	$ 2,156	$ 2,046
Common Stock, Par or Stated Value Per Share	$ 1	$ 1
Common Stock, Shares Authorized	100,000,000	100,000,000
Common Stock, Shares Issued	65,685,615	65,709,819
Common Stock, Restricted Shares	137,017	118,834
Treasury Stock, Shares	25,304,914	25,384,834