Amount of unrealized gain (loss) on investments in debt and equity securities classified as available-for-sale securities.

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This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting.

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The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Investments (Summary of Realized Gain (Loss) on Investments) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Schedule of Investments [Line Items]
Realized (losses) gains on investments	$ (166)	$ 3,188	$ 200	$ 5,679
Other-than-temporary impairment		(850)		(4,257)
Investment gains (losses), net	6,980	2,110	2,678	691
Other Investments [Member]
Schedule of Investments [Line Items]
Realized (losses) gains on investments
Unrealized gains (losses) on investments	25	(228)	(739)	(731)
Fixed Maturities [Member]
Schedule of Investments [Line Items]
Realized (losses) gains on investments	(166)	20	(159)	134
U.S. Treasury Securities and Obligations of U.S. Government [Member]
Schedule of Investments [Line Items]
Realized (losses) gains on investments
Corporate Bonds [Member]
Schedule of Investments [Line Items]
Realized (losses) gains on investments	(44)	(107)	(66)	(125)
Collateralized Corporate Bank Loans [Member]
Schedule of Investments [Line Items]
Realized (losses) gains on investments	23	8	70	56
Municipal Bonds [Member]
Schedule of Investments [Line Items]
Realized (losses) gains on investments	(145)	120	(164)	204
Mortgage Backed [Member]
Schedule of Investments [Line Items]
Realized (losses) gains on investments		(1)	1	(1)
Equity Securities [Member]
Schedule of Investments [Line Items]
Realized (losses) gains on investments		$ 3,168	359	$ 5,545
Equity Securities [Member] \| Other Investments [Member]
Schedule of Investments [Line Items]
Unrealized gains (losses) on investments	$ 7,121		$ 3,217