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- Definition

Percentage threshold that triggers a review of available for sale debt securities for declines in market value.

+ References

No definition available.

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- Definition

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

+ References

No definition available.

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- Definition

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

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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.

+ References

No definition available.

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months.

+ References

No definition available.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount of short-term investments classified as other.

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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.

+ References

No definition available.

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Investments (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
Investments (Narrative) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Percentage threshold that triggers a review of available for sale debt securities for declines in market value			80.00%
Aggregate market value of investments in unrealized loss position	$ 1,682,212		$ 1,682,212		$ 3,470,834
Gross unrealized losses on investments in unrealized loss position	48,271		48,271		130,602
Short-term investments	$ 368,898		$ 368,898		$ 174,131
Sales Revenue, Net [Member]
Schedule of Available-for-sale Securities [Line Items]
Percentage threshold of unrealized losses not exceeded by any one single issuer	5.00%	5.00%	5.00%	5.00%	0.80%
Sales Revenue, Net [Member] \| US Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Percentage threshold that triggers a review of available for sale debt securities for declines in market value					9.00%
Investment Grade [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, duration of unrealized loss, less than 12 months, gross unrealized depreciation	$ 1,291		$ 1,291		$ 68,010
Fixed maturity securities, duration of unrealized loss, greater than 12 months, gross unrealized depreciation	26,147		26,147		14,802
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Aggregate market value of investments in unrealized loss position	1,682,212		1,682,212		3,470,834
Gross unrealized losses on investments in unrealized loss position	48,271		48,271		130,602
Fixed maturity securities, duration of unrealized loss, less than 12 months, gross unrealized depreciation	9,667		9,667		105,810
Fixed maturity securities, duration of unrealized loss, greater than 12 months, gross unrealized depreciation	38,604		$ 38,604		$ 24,792
Fixed Maturity Securities [Member] \| Sales Revenue, Net [Member] \| US Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Percentage threshold that triggers a review of available for sale debt securities for declines in market value			0.50%
Limited Partnerships [Member]
Schedule of Available-for-sale Securities [Line Items]
Additional contractual commitments	565,479		$ 565,479
Private Placement Liquidiy Sweep [Member]
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	$ 305,548		$ 305,548