Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 14,029	$ 16,760
Common shares, shares issued	263,686,518	263,271,302
Common shares, shares outstanding	263,601,239	263,141,413
Treasury shares	85,279	129,889

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

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Number of previously issued common shares repurchased by the issuing entity and held in treasury.

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