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Investments (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net Investment Income [Line Items]
Net investment income earned	$ 52,443	$ 40,446	$ 141,227	$ 119,295
Fixed Income Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	45,088	38,865	130,903	113,424
Equity Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	2,079	1,605	5,876	4,492
Short-Term Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	867	396	2,001	1,023
Other Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	7,211	2,659	10,868	9,493
Investment Expenses [Member]
Net Investment Income [Line Items]
Net investment income earned	$ (2,802)	$ (3,079)	$ (8,421)	$ (9,137)

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- Definition

Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(2))
-URI http://asc.fasb.org/extlink&oid=114873790&loc=SL114874131-224263

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- Definition

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+ References

No definition available.

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