CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 3,846	$ 4,647
Preferred stock, par value (usd per share)	$ 10.00	$ 10.00
Preferred stock, shares authorized (shares)	1,000,000	1,000,000
Preferred stock, shares issued (shares)	0	0
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	100,000,000	100,000,000
Common stock, shares issued (shares)	48,147,969	48,147,969
Common stock, shares outstanding (shares)	48,147,969	48,147,969
Treasury stock (shares)	9,581,990	9,872,505

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

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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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