Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts, current	$ 58,630	$ 47,209
Accumulated amortization of other intangible assets	18,257	17,216
Allowance for doubtful accounts, noncurrent	$ 10,000	$ 10,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock authorized (in shares)	100,000,000	100,000,000
Common stock issued (in shares)	75,465,000	75,344,000
Common stock outstanding (in shares)	74,058,000	73,877,000
Common stock in treasury (in shares)	1,407,000	1,467,000

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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Face amount or stated value per share of common stock.

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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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