REINSURANCE (Detail) - Schedule of Reinsurance premiums written and earned (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Direct	$ 4,714,588	$ 4,398,753	$ 4,381,185
Direct	4,624,557	4,535,626	4,861,073
Assumed	2,183,696	1,862,578	1,730,126
Assumed	2,179,555	1,837,528	1,877,634
Ceded	(1,464,896)	(1,261,743)	(1,367,599)
Ceded	(1,477,000)	(1,342,017)	(1,586,968)
Net	5,433,388	4,999,588	4,743,712
Net	$ 5,327,112	$ 5,031,137	$ 5,151,739