Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Shareholders' equity
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Treasury Stock, Shares	41,587,480	41,523,470
Class A [Member]
Shareholders' equity
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	105,035,744	105,037,845
Class B [Member]
Shareholders' equity
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	0	0