CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Securities, available-for-sale, at fair value:
Fixed maturities, amortized cost	$ 4,567,873	$ 4,602,514
Shareholders' equity (note 14):
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	1,000,000us-gaap_CommonStockSharesAuthorized	1,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued (in shares)	340,079us-gaap_CommonStockSharesIssued	340,047us-gaap_CommonStockSharesIssued
Common stock, shares outstanding (in shares)	339,639us-gaap_CommonStockSharesOutstanding	338,560us-gaap_CommonStockSharesOutstanding
Treasury stock, shares at cost (in shares)	440us-gaap_TreasuryStockShares	1,487us-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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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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