This element represents the aggregate cost of investments accounted for under the equity method of accounting.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.12)

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 12

-Article 5

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.12)

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-Topic 323

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-Section 45

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- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, resulting from a business combination.

+ References

No definition available.

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- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

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The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

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Investments (Schedule of Investments in Other Ventures, under Equity Method) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended			0 Months Ended	1 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 01, 2008	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010	Dec. 01, 2013	Jan. 06, 1999	Sep. 30, 2013
Schedule of Equity Method Investments [Line Items]
Investment	$ 143,632	$ 139,382
Investments in other ventures, under equity method	120,713us-gaap_EquityMethodInvestments	105,616us-gaap_EquityMethodInvestments
Equity method investee, additional contribution	(1,030)	4,000	0
Tower Hill Companies
Schedule of Equity Method Investments [Line Items]
Investment	64,750	60,500
Investments in other ventures, under equity method	50,656	42,128
THIG
Schedule of Equity Method Investments [Line Items]
Investment	50,000	50,000		50,000
Ownership %	25.00%	25.00%		25.00%
Investments in other ventures, under equity method	20,811	25,107
Intangible Assets, Net				40,000
Goodwill				7,800
Tower Hill
Schedule of Equity Method Investments [Line Items]
Investment	10,000	10,000
Ownership %	30.30%	29.40%
Investments in other ventures, under equity method	18,991	14,506
Tower Hill Re
Schedule of Equity Method Investments [Line Items]
Investment	4,250	0
Ownership %	25.00%	0.00%
Investments in other ventures, under equity method	5,162	0
Tower Hill Signature
Schedule of Equity Method Investments [Line Items]
Investment	500	500
Ownership %	25.00%	25.00%
Investments in other ventures, under equity method	5,692	2,515
Top Layer Re
Schedule of Equity Method Investments [Line Items]
Investment	65,375	65,375							13,100
Ownership %	50.00%	50.00%							50.00%
Investments in other ventures, under equity method	60,911	50,500
Equity method investee, additional contribution					18,000	20,500	13,800
Angus
Schedule of Equity Method Investments [Line Items]
Investment	10,507	10,507
Ownership %	40.40%	42.50%						42.50%		38.80%
Investments in other ventures, under equity method	8,072	9,180
Goodwill								1,700
Other
Schedule of Equity Method Investments [Line Items]
Investment	3,000	3,000
Ownership %	22.00%	22.00%
Investments in other ventures, under equity method	$ 1,074	$ 3,808