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Reinsurance (Ceded Premiums and Losses Related to Flood Operations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Percentage of NFIP claims ceded to the federal government	100.00%
Ceded premiums written	$ (455,708)	$ (429,366)	$ (402,597)
Ceded premiums earned	(451,883)	(420,385)	(398,366)
Ceded loss and loss expense	(203,412)	(186,268)	(230,286)
National Flood Insurance Program [Member]
Ceded premiums written	(274,042)	(266,925)	(248,053)
Ceded premiums earned	(271,598)	(259,119)	(244,238)
Ceded loss and loss expense	$ (78,993)	$ (71,676)	$ (144,967)

X

- Definition

Percentage of unpaid NFIP claims ceded by federal government

+ References

No definition available.

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- Definition

Amount of earned premiums ceded to other entities.

+ References

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-Publisher FASB
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-SubTopic 235
-Section S99
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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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