Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Short-term investments	$ 18,974	$ 35,879
Accounts receivable allowance	18,899	17,830
Short-term finance receivables allowance	18,012	12,556
Long-term finance receivables allowance	17,857	7,095
Other assets	$ 355,799	$ 230,442
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, authorized (in shares)	480,000,000	480,000,000
Common stock issued (in shares)	323,337,912	323,337,912
Treasury stock (in shares)	151,362,724,000	152,888,969,000