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Significant Transactions (Details 3) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2010	Nov. 17, 2006	Dec. 30, 2011 Old Lyme
Business acquisition
Cash to be paid on acquisition					$ 6.0
Purchase note acquired					2.1
Share Repurchase
Authorized repurchase of common shares				1,000,000
Additional authorized repurchase of common shares			600,000
Common shares repurchased and retired during the period	157,629	246,284
Value of common shares repurchased and retired during the period	$ 76.0	$ 86.0
Shares remaining under share repurchase authorization	30,668

X

- Definition

Amount of cash paid to acquire the entity.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

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The amount of acquisition cost of a business combination allocated to the noncurrent portion of the long-term debt assumed from the acquired entity.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.



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-Name Emerging Issues Task Force (EITF)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.



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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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Number of shares that have been repurchased and retired during the period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

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-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644



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-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.



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-Name Regulation S-X (SX)

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-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.



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The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

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No definition available.

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- Definition

The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

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The number of additional shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

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