Balance Sheet Parentheticals (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts Receivable, Current	$ 16,074	$ 15,549
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	125,000,000	125,000,000
Common Stock, Shares, Issued	44,786,011	44,786,011
Common Stock, Shares, Outstanding	25,213,828	25,541,393
Treasury Stock, Shares	19,572,183	19,244,618

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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