Summary of Investments (Net Realized Investment Gains and Losses and Proceeds) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	$ (7,864)	$ 2,249
Available-for-sale Securities [Abstract]
Proceeds from sales	0	1,095
Gross realized gains	0	1,046
Gross realized losses	0	0
Discontinued Operations
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	(1,057)	1,705
Available-for-sale Securities [Abstract]
Proceeds from sales	0	3,964
Gross realized gains	0	1,254
Gross realized losses	0	(78)
Continuing and Discontinuing Operations
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	(8,921)	3,954
Fixed maturities: \| Available-for-sale
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	4	424
Fixed maturities: \| Change in fair value
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	(111)	371
Fixed maturities: \| Sales
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	556	57
Equity securities: \| Change in fair value
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	(9,188)	111
Equity securities: \| Sales
Gain (Loss) on Investments [Line Items]
Net realized investment gains (losses)	$ 875	$ 1,286

Debt Securities, Available-For-Sale, Realized Gain

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Debt Securities, Available-For-Sale, Realized Loss

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The cash inflow associated with the sale of debt securities classified as available-for-sale securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26853-111562

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-Publisher FASB
-Name Accounting Standards Codification
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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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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 210.7-04.3(a))
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

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-Publisher FASB
-Name Accounting Standards Codification
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