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Investments (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net Investment Income [Line Items]
Net investment income earned	$ 40,446	$ 33,375	$ 119,295	$ 95,326
Fixed Income Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	38,865	32,453	113,424	95,850
Equity Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	1,605	1,506	4,492	5,940
Short-Term Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	396	192	1,023	493
Other Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	2,659	1,628	9,493	(49)
Investment Expenses [Member]
Net Investment Income [Line Items]
Net investment income earned	$ (3,079)	$ (2,404)	$ (9,137)	$ (6,908)

X

- 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/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(2))
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 235
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-16(Column G))
-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574960-122915

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- Definition

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+ References

No definition available.

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