Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 8,427	$ 3,723
Amortizable intangible assets, accumulated amortization	$ 218,468	$ 168,452
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, authorized shares (in shares)	800,000,000	800,000,000
Common stock, issued shares (in shares)	324,418,632	324,418,632
Treasury stock, shares (in shares)	105,271,009	106,955,082