Ceded premiums on behalf of Markel CATCo Re.

No definition available.

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- Definition

Total amount of ceding fees received for front of certain contracts

+ References

No definition available.

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- Definition

Ceding fees earned during the period for fronting of certain contracts

+ References

No definition available.

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- Definition

Gross written premiums on behalf of Markel CATCo Re.

+ References

No definition available.

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- Definition

Loss exposure on certain contracts

+ References

No definition available.

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- Definition

Revenues attributable to management contracts with Nephila Funds and the Nephila Reinsurers

+ References

No definition available.

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- Definition

Amount of written premiums ceded to other entities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 605
-Section 50
-Paragraph 1
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- Definition

Amount of direct and assumed premiums written.

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-SubTopic 605
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- Definition

Amount, after valuation allowance, recoverable under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, policy benefits and policy reserves. Excludes premiums paid under reinsurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

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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Related Party Transactions Related Party Transactions (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Premiums Written, Gross	$ 2,255,042	$ 2,046,884
Ceded premiums written	777,949	712,082
Reinsurance Recoverables	5,292,335		$ 5,221,947
Nephila Funds and Nephila Reinsurers [Member]
Related Party Transaction [Line Items]
Revenues attributable to management contracts with Nephila Funds and the Nephila Reinsurers	43,200
Syndicate 2357 [Member]
Related Party Transaction [Line Items]
Premiums Written, Gross	93,000
Ceded premiums written	93,000
Reinsurance Recoverables	189,000		$ 179,800
Markel CATCo Re. Related Party Transaction 2 [Member]
Related Party Transaction [Line Items]
Ceding Fees	8,800
Ceding Fees, Earned	2,200
Loss exposure on certain contracts	191,600
Markel CATCo Re. Related Party Transaction 1 [Member]
Related Party Transaction [Line Items]
Gross written premiums on behalf of Markel CATCo Re.	4,000	5,500
Ceded premiums on behalf of Markel CATCo Re.	$ 4,000	$ 5,500