Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accounts receivable, allowance for doubtful accounts	$ 12,025	$ 12,001
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	72,386,017	72,024,329
Treasury stock, shares (in shares)	8,667,031	9,173,731