Fair Value of Financial Instruments (Carrying Amounts and Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Assets:
Equity securities	$ 830,212	$ 450,648
Loans receivable	262,341	325,219
Fair Value
Assets:
Fixed maturity securities	12,413,636	12,725,806
Equity securities available for sale	153,513	170,991
Equity securities	830,212	450,648
Loans receivable	262,341	325,219
Cash and cash equivalents	756,368	674,441
Trading account receivables from brokers and clearing organizations	41,576	371,034
Liabilities:
Trading account securities sold but not yet purchased	155,484	106,079
Subordinated debentures	338,660	332,640
Senior notes and other debt	2,025,469	2,344,292
Carrying Value
Assets:
Fixed maturity securities	12,395,810	12,705,160
Equity securities available for sale	153,513	170,991
Equity securities	830,212	450,648
Loans receivable	259,411	322,012
Cash and cash equivalents	756,368	674,441
Trading account receivables from brokers and clearing organizations	41,576	371,034
Due from broker fair value	39,795	23,133
Liabilities:
Trading account securities sold but not yet purchased	155,484	106,079
Subordinated debentures	340,190	340,060
Senior notes and other debt	$ 1,843,865	$ 2,115,527

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Fair value portion of liabilities pertaining to principal and customer trading transactions, or which may be incurred with the objective of generating a profit from short-term fluctuations in price as part of an entity's market-making, hedging and proprietary trading. Examples include, but are not limited to, short positions in securities, derivatives and commodities.

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Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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Due from broker fair value

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Marketable Securities, Fair Value Disclosure

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