CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
CONSOLIDATED BALANCE SHEETS [Abstract]
Allowance for doubtful accounts	$ 2,551	$ 3,125
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	480,000,000	480,000,000
Common stock, shares outstanding	132,516,000	132,371,000