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Reinsurance (Ceded Premiums and Losses Related to Flood Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Ceded premiums written	$ (115,634)	$ (108,250)	$ (326,939)	$ (308,846)
Ceded premiums earned	(105,608)	(98,704)	(311,105)	(295,232)
Ceded loss and loss expenses incurred	(43,305)	(104,757)	$ (145,712)	(175,786)
National Flood Insurance Program [Member]
Percentage of NFIP claims ceded by federal government			100.00%
Ceded premiums written	(74,864)	(70,100)	$ (206,451)	(193,110)
Ceded premiums earned	(65,847)	(61,448)	(191,914)	(180,582)
Ceded loss and loss expenses incurred	$ (27,459)	$ (89,396)	$ (62,208)	$ (115,376)

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- Definition

Percentage of unpaid NFIP claims ceded to federal government.

+ References

No definition available.

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Amount of earned premiums ceded to other entities.

+ References

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-Publisher FASB
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-SubTopic 235
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Amount of written premiums ceded to other entities.

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Amount of reduction of provision for policy benefits and costs incurred for policies ceded.

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