CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Accounts receivable, allowance for credit loss	$ 11,190	$ 12,260
Accumulated depreciation and amortization	$ 836,579	$ 823,024
Common stock of $.10 par value:
Common stock, par value (in usd per share)	$ 0.10	$ 0.10
Class A Common Stock
Common stock of $.10 par value:
Authorized shares (in shares)	300,000,000	300,000,000
Issued shares (in shares)	176,662,108	176,288,596
Treasury shares (in shares)	12,808,394	12,004,865
Class B Common Stock
Common stock of $.10 par value:
Authorized shares (in shares)	780,724	780,724
Issued shares (in shares)	780,724	780,724