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Reinsurance (Ceded Premiums and Losses Related to Flood Operations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Ceded premiums written	$ (100,002)	$ (95,945)
Ceded premiums earned	(102,026)	(98,029)
Ceded loss and loss expenses incurred	$ (43,343)	(43,979)
National Flood Insurance Program [Member]
Percentage of NFIP claims ceded by federal government	100.00%
Ceded premiums written	$ (60,013)	(56,669)
Ceded premiums earned	(62,263)	(58,991)
Ceded loss and loss expenses incurred	$ (13,686)	$ (15,719)

X

- Definition

Percentage of unpaid NFIP claims ceded to federal government.

+ References

No definition available.

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X

- Definition

Amount of earned premiums ceded to other entities.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 235
-Section S99
-Paragraph 2
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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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