Consolidated Balance Sheets Parenthetical (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 7,073	$ 6,837
Common stock stated value per share (USD per share)	$ 20	$ 20
Authorized	50,000,000us-gaap_CommonStockSharesAuthorized	50,000,000us-gaap_CommonStockSharesAuthorized
Issued to voting trustees	13,159,559	13,164,362
Issued to shareholders	2,714,853	2,765,577
In treasury, at cost	(14,482)us-gaap_TreasuryStockShares	(41,576)us-gaap_TreasuryStockShares
Outstanding Common Stock	15,859,930us-gaap_CommonStockSharesOutstanding	15,888,363us-gaap_CommonStockSharesOutstanding
Common Stock, Shares Subscribed	806,811	744,241
Subscripton Receivable	(806,811)	(744,241)

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Issued to voting trustees

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Subscription Receivable

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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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Amount of common stock allocated to investors to buy shares of a new issue of common stock before they are offered to the public. When stock is sold on a subscription basis, the issuer does not initially receive the total proceeds. In general, the issuer does not issue the shares to the investor until it receives the entire proceeds.

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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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