INVESTMENTS (Detail) - Net investment income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Fixed maturities, short-term investments and cash equivalents	$ 1,178,038	$ 1,245,185	$ 1,369,503
Equity securities and other investments	17,804	20,693	13,753
Funds withheld	12,240	12,738	14,649
Total gross investment income	1,208,082	1,278,616	1,397,905
Investment expenses	(70,313)	(80,578)	(78,082)
Net investment income	$ 1,137,769	$ 1,198,038	$ 1,319,823