Consolidated Balance Sheet (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheet [Abstract]
Trade receivables, allowance for doubtful accounts	$ 7,043	$ 9,391
Percentage of cumulative preferred stock	4.50%	4.50%
Preferred stock, par value	$ 50	$ 50
Preferred stock, callable per share	$ 52.50	$ 52.50
Common stock, no par value
Common stock, shares outstanding	36,692,590	36,519,726

Total number of shares of common stock held by shareholders. May be all or portion of the number of common shares authorized. These shares represent the ownership interest of the common shareholders. Shares outstanding equals shares issued minus shares held in treasury and other adjustments, if any.

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Face amount or stated value per share of nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer); generally not indicative of the fair market value per share.

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- Definition

The price per share at which the preferred stock of an entity that has priority over common stock in the distribution of dividends and in the event of liquidation of the entity is redeemed or may be called at. The redemption features of this preferred stock are solely within the control of the issuer.

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