Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Equity securities, cost	$ 2,366,035	$ 1,804,698
Debt securities, amortized cost	$ 14,364,430	$ 14,875,750
Common stock, shares authorized	22,000,000us-gaap_CommonStockSharesAuthorized	22,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	17,459,961us-gaap_CommonStockSharesIssued	17,459,961us-gaap_CommonStockSharesIssued
Treasury stock, shares	1,405,638us-gaap_TreasuryStockShares	693,769us-gaap_TreasuryStockShares

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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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 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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