CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Balance Sheet Parenthetical Disclosures
Accounts receivable, allowance (in dollars)	$ 4,516	$ 4,425
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	469,725,220	469,435,678
Common stock, shares outstanding	469,725,220	469,435,678