Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 5,810	$ 3,723
Indefinite-lived and amortizable intangible assets, accumulated amortization	$ 184,669	$ 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)	106,066,299	106,955,082