Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Allowances for Accounts Receivable (in dollars)	$ 9,730	$ 8,943	$ 9,055
Preferred stock-issued	0	0	0
Common Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized	245,000,000	245,000,000	245,000,000
Common stock, shares issued	133,513,000	133,247,000	133,159,000
Common stock, shares outstanding	82,728,000	82,616,000	83,046,000
Treasury stock-shares at cost	50,785,000	50,631,000	50,113,000
Preferred Class A [Member]
Preferred stock-par value	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock- shares authorized	5,000,000	5,000,000	5,000,000
Preferred Class B [Member]
Preferred stock-par value	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock- shares authorized	60,000	60,000	60,000

Amount of allowance for credit loss on accounts receivable, classified as current.

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