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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

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- 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 + Details
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- 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 + Details
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