UNAUDITED QUARTERLY FINANCIAL DATA (Detail) - Unaudited quarterly financial data (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
2011
Net premiums earned – property and caualty operations	$ 5,327,112	$ 5,031,137	$ 5,151,739
Net premiums earned – life operations	363,018	382,924	555,101
Net income (loss) attributable to ordinary shareholders	(474,760)	585,472	206,607
Net income (loss) per ordinary share and ordinary share equivalent – basic (in Dollars per share)	$ (1.52)	$ 1.74	$ 0.61
Net income (loss) per ordinary share and ordinary share equivalent – diluted (in Dollars per share)	$ (1.52)	$ 1.73	$ 0.61
First Quarter [Member]
2011
Net premiums earned – property and caualty operations	1,271,696	1,263,601
Net premiums earned – life operations	89,687	104,884
Underwriting profit (loss) - property and casualty operations	(328,064)	(6,610)
Net income (loss) attributable to ordinary shareholders	(227,284)	127,996
Net income (loss) per ordinary share and ordinary share equivalent – basic (in Dollars per share)	$ (0.73)	$ 0.37
Net income (loss) per ordinary share and ordinary share equivalent – diluted (in Dollars per share)	$ (0.73)	$ 0.37
Second Quarter [Member]
2011
Net premiums earned – property and caualty operations	1,306,125	1,216,313
Net premiums earned – life operations	92,214	86,448
Underwriting profit (loss) - property and casualty operations	67,049	94,673
Net income (loss) attributable to ordinary shareholders	225,663	191,811
Net income (loss) per ordinary share and ordinary share equivalent – basic (in Dollars per share)	$ 0.73	$ 0.56
Net income (loss) per ordinary share and ordinary share equivalent – diluted (in Dollars per share)	$ 0.69	$ 0.56
Third Quarter [Member]
2011
Net premiums earned – property and caualty operations	1,362,532	1,268,741
Net premiums earned – life operations	90,794	96,586
Underwriting profit (loss) - property and casualty operations	(22,200)	64,666
Net income (loss) attributable to ordinary shareholders	42,398	77,543
Net income (loss) per ordinary share and ordinary share equivalent – basic (in Dollars per share)	$ 0.14	$ 0.23
Net income (loss) per ordinary share and ordinary share equivalent – diluted (in Dollars per share)	$ 0.14	$ 0.23
Fourth Quarter [Member]
2011
Net premiums earned – property and caualty operations	1,386,759	1,282,482
Net premiums earned – life operations	90,323	95,006
Underwriting profit (loss) - property and casualty operations	(114,138)	109,765
Net income (loss) attributable to ordinary shareholders	$ (515,537)	$ 188,122
Net income (loss) per ordinary share and ordinary share equivalent – basic (in Dollars per share)	$ (1.62)	$ 0.58
Net income (loss) per ordinary share and ordinary share equivalent – diluted (in Dollars per share)	$ (1.62)	$ 0.57