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Senior Long-Term Debt And Other Debt	6 Months Ended
	Jun. 30, 2015
Debt Disclosure [Abstract]
Senior Long-Term Debt And Other Debt	Senior Long-Term Debt and Other Debt Alterra Capital Holdings Limited and Markel Bermuda Limited are party to a secured credit facility, which expires on December 15, 2015. On May 19, 2015, the Company reduced the capacity of the secured credit facility from $650 million to $550 million.

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- References

No definition available.

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- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 505



-SubTopic 10



-Section 50



-Paragraph 3



-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 210



-SubTopic 10



-Section S99



-Paragraph 1



-Subparagraph (SX 210.5-02.19,20,22)



-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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