Consolidated Balance Sheets (Parenthetical) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Stockholders' equity
Accounts Receivable, Allowance for Credit Loss, Current	$ 5,032,000	$ 5,409,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares outstanding	47,035,634	46,990,031
Treasury stock, shares	35,016,619	35,062,222