Condensed Consolidated Balance Sheets Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 6,896	$ 7,073
Common, stated value per share	$ 20	$ 20
Authorized	50,000,000us-gaap_CommonStockSharesAuthorized	50,000,000us-gaap_CommonStockSharesAuthorized
Issued to voting trustees	13,497,274	13,159,559
Issued to shareholders	2,745,417	2,714,853
In treasury, at cost	(197,399)us-gaap_TreasuryStockShares	(14,482)us-gaap_TreasuryStockShares
Outstanding common stock	16,045,292us-gaap_CommonStockSharesOutstanding	15,859,930us-gaap_CommonStockSharesOutstanding

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Issued to voting trustees

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- Definition

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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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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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 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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