This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563

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Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
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This element represents the amount of loss recognized for other than temporary impairments (OTTI) of investments in debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 5.M)
-URI http://asc.fasb.org/extlink&oid=65877573&loc=d3e87990-122713

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The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In AOCI

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Securities In An Unrealized Loss Position (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) shares	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) shares	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Aggregate Fair Value	$ 4,162,130		$ 4,162,130		$ 5,160,888
Gross unrealized losses	51,829		51,829		99,268
Other-than-temporary impairments	0	$ 0	0	$ 18,114
Common stock
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairments				$ 18,100
Common stock
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses	$ 5,700		$ 5,700
Noninvestment Grade Investments
Schedule of Available-for-sale Securities [Line Items]
Number of securities \| shares	1		1
Preferred stocks
Schedule of Available-for-sale Securities [Line Items]
Aggregate Fair Value	$ 24,589		$ 24,589		22,034
Gross unrealized losses	1,084		1,084		3,639
Common stock
Schedule of Available-for-sale Securities [Line Items]
Aggregate Fair Value	33,044		33,044		9,091
Other-than-temporary impairment, available for sale securities			33,000
Gross unrealized losses	$ 5,691		$ 5,691		$ 1,046