Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowances for accounts receivable	$ 10,701	$ 11,162
Accumulated amortization of operating lease	48,514	46,045
Accumulated amortization of intangibles	$ 147,225	$ 143,097
Preferred stock, par value (in USD per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in USD per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	87,850,292	87,850,292
Treasury stock, shares (in shares)	37,327,627	37,454,209