Consolidated Balance Sheets (Parentheticals) - USD ($) $ / shares in Thousands	Dec. 31, 2020	Dec. 31, 2019
Allowance for doubtful accounts	$ 55,660	$ 53,708
Valuation allowance for deferred tax asset	$ 330,249	$ 369,729
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares issued (in shares)	131,124,989	131,124,989
Common stock, shares outstanding (in shares)	131,124,989	131,124,989

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

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Face amount per share of no-par value common stock.

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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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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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