Consolidated Balance Sheets (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 183,829	$ 167,282
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred Stock, Par or Stated Value Per Share	$ 1	$ 1
Preferred Stock, Shares Authorized	200,000us-gaap_PreferredStockSharesAuthorized	200,000us-gaap_PreferredStockSharesAuthorized
Preferred Stock, Shares Issued	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Common Stock, Par or Stated Value Per Share	$ 1	$ 1
Common Stock, Shares Authorized	50,000,000us-gaap_CommonStockSharesAuthorized	50,000,000us-gaap_CommonStockSharesAuthorized
Common Stock, Shares, Issued	27,518,226us-gaap_CommonStockSharesIssued	27,189,922us-gaap_CommonStockSharesIssued
Treasury Stock, Shares	385,942us-gaap_TreasuryStockShares	330,487us-gaap_TreasuryStockShares

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Face amount or stated value per share of common stock.

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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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