Fair Value (Details - Hierarchy table) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	$ 13,412,011	$ 13,918,745
Short-term investments	20,055	25,678
Equities	1,320,284	1,056,514
Other invested assets	95,115	111,476
Funds held - directly managed	434,548	472,593
Total	15,282,013	15,585,006
Derivative assets [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	15,414	20,033
Derivative assets [Member] | Foreign currency option contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	1,848
Derivative assets [Member] | Futures contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		846
Derivative assets [Member] | Insurance-linked securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	23	3
Derivative assets [Member] | Total return swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	1,061	485
Derivative assets [Member] | TBAs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	1,409	154
Derivative liabilities [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	(7,623)	(7,446)
Derivative liabilities [Member] | Foreign currency option contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		(1,196)
Derivative liabilities [Member] | Futures contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	(21,382)	(467)
Derivative liabilities [Member] | Insurance-linked securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	(343)	(339)
Derivative liabilities [Member] | Total return swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	(2,118)	(2,007)
Derivative liabilities [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	(21,074)	(16,282)
Derivative liabilities [Member] | TBAs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		(240)
Notes And Loan Receivables And Notes Securitization [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	51,103	44,817
Annuities and residuals [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	12,155	13,243
Private equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	64,642	59,872
Other invested assets funds held directly managed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Funds held - directly managed	12,008	13,398
Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Funds held - directly managed	10,984
Real estate investment trust [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	177,130	213,770
Insurance [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	128,521	145,437
Consumer noncyclical [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	113,740	100,134
Energy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	108,648	123,978
Finance [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	104,378	98,328
Technology [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	65,311	61,262
Consumer cyclical [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	59,747	39,002
Industrials [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	58,435	49,983
Communications [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	53,388	54,469
Utilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	28,946	31,748
Other equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	21,959	11,571
Mutual funds and exchange traded funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	400,081	126,832
US Government and government sponsored enterpises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	2,299,063	2,315,422
Funds held - directly managed	155,341	153,483
US states, territories and municipalities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	621,071	530,603
Funds held - directly managed	132	132
Non US sovereign government supranational and government related [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	1,557,126	1,976,202
Funds held - directly managed	111,021	128,233
Corporate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	5,494,967	5,604,160
Funds held - directly managed	145,062	177,347
Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	1,121,698	1,131,420
Residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	2,263,463	2,306,476
Other mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	54,623	54,462
Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Short-term investments	0	0
Equities	1,017,682	1,004,505
Other invested assets	(21,382)	379
Funds held - directly managed	0	0
Total	996,300	1,004,884
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Foreign currency option contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Futures contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		846
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Insurance-linked securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Total return swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | TBAs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Foreign currency option contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		0
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Futures contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	(21,382)	(467)
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Insurance-linked securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Total return swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | TBAs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		0
Quoted prices in active markets for identical assets (Level 1) | Notes And Loan Receivables And Notes Securitization [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Quoted prices in active markets for identical assets (Level 1) | Annuities and residuals [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Quoted prices in active markets for identical assets (Level 1) | Private equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Quoted prices in active markets for identical assets (Level 1) | Other invested assets funds held directly managed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Funds held - directly managed	0	0
Quoted prices in active markets for identical assets (Level 1) | Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Funds held - directly managed	0
Quoted prices in active markets for identical assets (Level 1) | Real estate investment trust [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	177,130	213,770
Quoted prices in active markets for identical assets (Level 1) | Insurance [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	123,839	140,916
Quoted prices in active markets for identical assets (Level 1) | Consumer noncyclical [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	113,740	100,134
Quoted prices in active markets for identical assets (Level 1) | Energy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	108,648	123,978
Quoted prices in active markets for identical assets (Level 1) | Finance [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	75,760	70,621
Quoted prices in active markets for identical assets (Level 1) | Technology [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	56,709	52,707
Quoted prices in active markets for identical assets (Level 1) | Consumer cyclical [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	59,747	39,002
Quoted prices in active markets for identical assets (Level 1) | Industrials [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	58,435	49,983
Quoted prices in active markets for identical assets (Level 1) | Communications [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	50,665	51,829
Quoted prices in active markets for identical assets (Level 1) | Utilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	28,946	31,748
Quoted prices in active markets for identical assets (Level 1) | Other equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	21,959	11,571
Quoted prices in active markets for identical assets (Level 1) | Mutual funds and exchange traded funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	142,104	118,246
Quoted prices in active markets for identical assets (Level 1) | US Government and government sponsored enterpises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Funds held - directly managed	0	0
Quoted prices in active markets for identical assets (Level 1) | US states, territories and municipalities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Funds held - directly managed	0	0
Quoted prices in active markets for identical assets (Level 1) | Non US sovereign government supranational and government related [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Funds held - directly managed	0	0
Quoted prices in active markets for identical assets (Level 1) | Corporate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Funds held - directly managed	0	0
Quoted prices in active markets for identical assets (Level 1) | Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Quoted prices in active markets for identical assets (Level 1) | Residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Quoted prices in active markets for identical assets (Level 1) | Other mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	12,812,745	13,319,099
Short-term investments	20,055	25,678
Equities	12,768	11,875
Other invested assets	(10,026)	(4,977)
Funds held - directly managed	422,408	459,063
Total	13,257,950	13,810,738
Significant other observable inputs (Level 2) | Derivative assets [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	15,414	20,033
Significant other observable inputs (Level 2) | Derivative assets [Member] | Foreign currency option contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	1,848
Significant other observable inputs (Level 2) | Derivative assets [Member] | Futures contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		0
Significant other observable inputs (Level 2) | Derivative assets [Member] | Insurance-linked securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant other observable inputs (Level 2) | Derivative assets [Member] | Total return swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant other observable inputs (Level 2) | Derivative assets [Member] | TBAs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	1,409	154
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	(7,623)	(7,446)
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Foreign currency option contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		(1,196)
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Futures contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Insurance-linked securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Total return swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	(21,074)	(16,282)
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | TBAs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		(240)
Significant other observable inputs (Level 2) | Notes And Loan Receivables And Notes Securitization [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant other observable inputs (Level 2) | Annuities and residuals [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant other observable inputs (Level 2) | Private equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant other observable inputs (Level 2) | Other invested assets funds held directly managed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Funds held - directly managed	0	0
Significant other observable inputs (Level 2) | Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Funds held - directly managed	10,984
Significant other observable inputs (Level 2) | Real estate investment trust [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant other observable inputs (Level 2) | Insurance [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	4,682	4,521
Significant other observable inputs (Level 2) | Consumer noncyclical [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant other observable inputs (Level 2) | Energy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant other observable inputs (Level 2) | Finance [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	8,086	7,354
Significant other observable inputs (Level 2) | Technology [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant other observable inputs (Level 2) | Consumer cyclical [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant other observable inputs (Level 2) | Industrials [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant other observable inputs (Level 2) | Communications [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant other observable inputs (Level 2) | Utilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant other observable inputs (Level 2) | Other equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant other observable inputs (Level 2) | Mutual funds and exchange traded funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant other observable inputs (Level 2) | US Government and government sponsored enterpises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	2,299,063	2,315,422
Funds held - directly managed	155,341	153,483
Significant other observable inputs (Level 2) | US states, territories and municipalities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	473,388	380,875
Funds held - directly managed	0	0
Significant other observable inputs (Level 2) | Non US sovereign government supranational and government related [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	1,557,126	1,976,202
Funds held - directly managed	111,021	128,233
Significant other observable inputs (Level 2) | Corporate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	5,494,967	5,604,160
Funds held - directly managed	145,062	177,347
Significant other observable inputs (Level 2) | Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	670,115	681,502
Significant other observable inputs (Level 2) | Residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	2,263,463	2,306,476
Significant other observable inputs (Level 2) | Other mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	54,623	54,462
Significant unobservable inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	599,266	599,646
Short-term investments	0	0
Equities	289,834	40,134
Other invested assets	126,523	116,074
Funds held - directly managed	12,140	13,530
Total	1,027,763	769,384
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Foreign currency option contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Futures contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		0
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Insurance-linked securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	23	3
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Total return swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	1,061	485
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | TBAs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Foreign exchange forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Foreign currency option contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		0
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Futures contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Insurance-linked securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	(343)	(339)
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Total return swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	(2,118)	(2,007)
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	0	0
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | TBAs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		0
Significant unobservable inputs (Level 3) [Member] | Notes And Loan Receivables And Notes Securitization [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	51,103	44,817
Significant unobservable inputs (Level 3) [Member] | Annuities and residuals [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	12,155	13,243
Significant unobservable inputs (Level 3) [Member] | Private equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	64,642	59,872
Significant unobservable inputs (Level 3) [Member] | Other invested assets funds held directly managed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Funds held - directly managed	12,008	13,398
Significant unobservable inputs (Level 3) [Member] | Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Funds held - directly managed	0
Significant unobservable inputs (Level 3) [Member] | Real estate investment trust [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant unobservable inputs (Level 3) [Member] | Insurance [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant unobservable inputs (Level 3) [Member] | Consumer noncyclical [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant unobservable inputs (Level 3) [Member] | Energy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant unobservable inputs (Level 3) [Member] | Finance [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	20,532	20,353
Significant unobservable inputs (Level 3) [Member] | Technology [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	8,602	8,555
Significant unobservable inputs (Level 3) [Member] | Consumer cyclical [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant unobservable inputs (Level 3) [Member] | Industrials [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant unobservable inputs (Level 3) [Member] | Communications [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	2,723	2,640
Significant unobservable inputs (Level 3) [Member] | Utilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant unobservable inputs (Level 3) [Member] | Other equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	0	0
Significant unobservable inputs (Level 3) [Member] | Mutual funds and exchange traded funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equities	257,977	8,586
Significant unobservable inputs (Level 3) [Member] | US Government and government sponsored enterpises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Funds held - directly managed	0	0
Significant unobservable inputs (Level 3) [Member] | US states, territories and municipalities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	147,683	149,728
Funds held - directly managed	132	132
Significant unobservable inputs (Level 3) [Member] | Non US sovereign government supranational and government related [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Funds held - directly managed	0	0
Significant unobservable inputs (Level 3) [Member] | Corporate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Funds held - directly managed	0	0
Significant unobservable inputs (Level 3) [Member] | Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	451,583	449,918
Significant unobservable inputs (Level 3) [Member] | Residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Significant unobservable inputs (Level 3) [Member] | Other mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	$ 0	$ 0