Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Investments
Fixed maturity securities, available for sale, amortized cost	$ 6,352,737	$ 5,921,487
Equity securities, available for sale, cost	$ 291,070	$ 464,388
SHAREHOLDERS' EQUITY
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	250,000us-gaap_CommonStockSharesAuthorized	250,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	126,472us-gaap_CommonStockSharesIssued	125,577us-gaap_CommonStockSharesIssued
Common stock, shares outstanding	96,521us-gaap_CommonStockSharesOutstanding	100,336us-gaap_CommonStockSharesOutstanding
Treasury stock	29,951us-gaap_TreasuryStockNumberOfSharesHeld	25,241us-gaap_TreasuryStockNumberOfSharesHeld

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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