DERIVATIVE INSTRUMENTS (Detail) - Earnings relating to derivative instruments not formally designated as hedging instruments (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Total derivatives not designated as hedging instruments	$ (8,863)	$ (20,168)	$ (33,273)
Amount of gain (loss) recognized in income from ineffective portion of fair value hedges	(1,875)	(13,675)	(374)
Net realized and unrealized gains (losses) on derivative instruments	(10,738)	(33,843)	(33,647)
Investment Related Derivatives [Member]
Interest rate exposure	(1,021)	3,511	9,124
Foreign exchange exposure	(302)	(15,642)	9,387
Credit exposure	(16,527)	(6,315)	(51,579)
Financial market exposure	(4,827)	2,125	3,359
Commodity exposure	(304)	0	0
Financial Operations Derivatives [Member]
Credit exposure	16,976	(7,281)	(2,667)
Other Non-Investment Derivatives [Member]
Contingent capital facility	(6,068)	(8,233)	(8,132)
Guaranteed minimum income benefit contract	(1,300)	1,719	4,644
Modified coinsurance funds withheld contract	4,510	9,948	(388)
Weather and Energy Derivatives [Member]
Structured weather risk management products	0	0	2,979
Derivatives Not Designated As Hedging Instruments [Member]
Net realized and unrealized gains (losses) on derivative instruments	$ (10,738)	$ 33,843	$ (33,647)