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Investments (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net Investment Income [Line Items]
Net investment income earned	$ 43,231	$ 37,419
Fixed Income Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	42,041	36,891
Equity Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	1,977	1,468
Short-Term Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	523	250
Other Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	1,563	1,603
Investment Expenses [Member]
Net Investment Income [Line Items]
Net investment income earned	$ (2,873)	$ (2,793)

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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