Amount of unrealized and realized gain (loss) on investment in debt and equity securities.

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Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Investments (Major Categories of Net Investment Gains (Losses) on Investments) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Gain (Loss) on Securities [Line Items]
Investment (losses) gains, net	$ (1,342)	$ 6,980	$ 17,412	$ 2,678
Debt Securities [Member]
Gain (Loss) on Securities [Line Items]
Gain (loss) on investments	175	(166)	4,376	200
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Gain (loss) on equity securities				359
Unrealized (losses) gains on equity securities	(1,941)	7,121	11,175	3,217
Other Investments [Member]
Gain (Loss) on Securities [Line Items]
Unrealized (losses) gains on equity securities	424	25	1,861	(739)
U.S. Treasury Securities and Obligations of U.S. Government [Member] \| Debt Securities [Member]
Gain (Loss) on Securities [Line Items]
Gain (loss) on debt securities
Corporate Bonds [Member] \| Debt Securities [Member]
Gain (Loss) on Securities [Line Items]
Gain (loss) on debt securities	154	(44)	171	(66)
Collateralized Corporate Bank Loans [Member] \| Debt Securities [Member]
Gain (Loss) on Securities [Line Items]
Gain (loss) on debt securities	(103)	23	(65)	70
Municipal Bonds [Member] \| Debt Securities [Member]
Gain (Loss) on Securities [Line Items]
Gain (loss) on debt securities	$ 124	$ (145)	4,271	(164)
Mortgage Backed [Member] \| Debt Securities [Member]
Gain (Loss) on Securities [Line Items]
Gain (loss) on debt securities			$ (1)	$ 1