v2.3.0.15

Segment Reporting Disclosures (Reconciliation Of Segment Assets To The Company's Consolidated Balance Sheets (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 11,371,754	$ 10,825,589
Investing [Member] | Segment Assets [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	8,572,794	8,198,401
Segment Assets [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	10,902,650	10,472,022
Segment Assets [Member] | Underwriting [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	2,329,856	2,273,621
Non-Insurance Operations [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 469,104	$ 353,567

X

- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 7

-Section 03

-Paragraph 12



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

-Topic 210

-SubTopic 10

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

-Section S99

-Name Accounting Standards Codification

-Publisher FASB

-Paragraph 1



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Concepts (CON)

-Number 6

-Paragraph 25

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 18

-Article 5



Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.18)

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

+ Details

Name:	us-gaap_Assets
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- 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.

+ Details

Name:	us-gaap_SegmentReportingAssetReconcilingItemLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration