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Investments (OTTI by Asset Type) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OTTI Losses Gross	$ 4,809	$ 8,509	$ 18,366
OTTI included in OCI	(36)	10	0
Total OTTI charges recognized in earnings	4,845	8,499	18,366
Other Investments [Member]
OTTI Losses Gross	190
OTTI included in OCI	0
Total OTTI charges recognized in earnings	190
AFS Fixed Income Securities [Member]
OTTI Losses Gross	3,184	5,191	2,189
OTTI included in OCI	(36)	10	0
Total OTTI charges recognized in earnings	3,220	5,181	2,189
AFS Fixed Income Securities [Member] | US Government Agencies Debt Securities [Member]
OTTI Losses Gross	36
OTTI included in OCI	0
Total OTTI charges recognized in earnings	36
AFS Fixed Income Securities [Member] | Obligations of States and Political Subdivisions [Member]
OTTI Losses Gross	612	2,797
OTTI included in OCI	0	0
Total OTTI charges recognized in earnings	612	2,797
AFS Fixed Income Securities [Member] | Corporate Securities [Member]
OTTI Losses Gross	587	1,880	2,188
OTTI included in OCI	0	0	0
Total OTTI charges recognized in earnings	587	1,880	2,188
AFS Fixed Income Securities [Member] | Collateralized Loan Obligations and Other Asset-Backed Securities [Member]
OTTI Losses Gross	96	19
OTTI included in OCI	0	0
Total OTTI charges recognized in earnings	96	19
AFS Fixed Income Securities [Member] | Commercial Mortgage Backed Securities [Member]
OTTI Losses Gross	670	220
OTTI included in OCI	0	0
Total OTTI charges recognized in earnings	670	220
AFS Fixed Income Securities [Member] | Residential Mortgage Backed Securities [Member]
OTTI Losses Gross	1,183	275	1
OTTI included in OCI	(36)	10	0
Total OTTI charges recognized in earnings	1,219	265	1
Available-for-sale Securities [Member] | Equity Securities [Member]
OTTI Losses Gross	1,435	3,318	16,177
OTTI included in OCI	0	0	0
Total OTTI charges recognized in earnings	1,435	3,318	16,177
Common Stock [Member] | Available-for-sale Securities [Member] | Equity Securities [Member]
OTTI Losses Gross	1,435	3,316	15,996
OTTI included in OCI	0	0	0
Total OTTI charges recognized in earnings	$ 1,435	3,316	15,996
Nonredeemable Preferred Stock [Member] | Available-for-sale Securities [Member] | Equity Securities [Member]
OTTI Losses Gross		2	181
OTTI included in OCI		0	0
Total OTTI charges recognized in earnings		$ 2	$ 181

X

- Definition

The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=82895926&loc=d3e25351-111560

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X

- Definition

Amount before tax of other than temporary impairment (OTTI) loss on investments in available-for-sale and held-to-maturity debt securities, recognized in other comprehensive loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669646-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=82895926&loc=d3e25362-111560

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X

- Definition

The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 8B
-URI http://asc.fasb.org/extlink&oid=82897076&loc=SL6284393-111563

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