CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Property and equipment, Accumulated depreciation	$ 60,284	$ 62,206
Common stock, shares authorized (shares)	180,000,000us-gaap_CommonStockSharesAuthorized	180,000,000us-gaap_CommonStockSharesAuthorized
Common stock, issued (shares)	92,322,905us-gaap_CommonStockSharesIssued	92,313,182us-gaap_CommonStockSharesIssued
Common stock, outstanding (shares)	92,302,636us-gaap_CommonStockSharesOutstanding	92,292,913us-gaap_CommonStockSharesOutstanding
Treasury stock, shares (shares)	20,269us-gaap_TreasuryStockShares	20,269us-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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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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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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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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