TAXATION (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Income Tax Examination, Description	The Company believes that these examinations will be concluded within the next 24 months; however, it is not currently possible to estimate the outcome of these examinations.
Income Tax Years Open For Potential Examination	The Company has open tax years that are potentially subject to examinations by local tax authorities, in the following major tax jurisdictions: the U.S., 2010 and 2011; the U.K., 2009 to 2011; Switzerland, 2007 to 2011; Ireland, 2005 to 2011; Germany, 2010 and 2011; and France, 2007 to 2011.
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	35.00%
Deferred Tax Assets (Liabilities), Net	$ 115,601,000	$ 143,525,000
Deferred Tax Liabilities, Current	98,420,000	105,667,000
Deferred Tax Assets, Valuation Allowance	497,236,000	514,467,000
Operating Losses Expire Amount	35,200,000
Realized Capital Losses Expire Amount	305,600,000
Valuation Allowance, Amount	119,300,000
Ireland [Member] | Ireland [Member]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	25.00%
Ireland [Member]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	12.50%
Operating Loss Carryforwards	189,500,000
Bermuda [Member]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	0.00%
U.K [Member]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	26.50%
Valuation Allowance, Amount	22,200,000
Operating Loss Carryforwards	96,500,000
Switzerland [Member] | Expire At The End Of 2012 [Member]
Operating Loss Carryforwards	803,300,000
Switzerland [Member]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	7.83%
Germany [Member]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	15.00%
France [Member]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	34.43%
Other Swiss [Member] | Expire At The End Of 2012 [Member]
Valuation Allowance, Amount	183,800,000
Other Swiss [Member]
Operating Loss Carryforwards	74,300,000
Irish Losses [Member]
Valuation Allowance, Amount	53,100,000
Operating Loss Carryforwards	158,000,000
U.K Group [Member]
Operating Loss Carryforwards	88,400,000
Switzerland [Member]
Operating Loss Carryforwards	881,200,000
Switzerland [Member] | Switzerland [Member]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	21.20%
United States [Member]
Unrealized Capital Loss Carry Forwards	340,800,000
Unrealized Capital Loss Carry Forwards Tax Effected	119,300,000
Unites States Group [Member]
Unrealized Capital Loss Carry Forwards	336,800,000
Unrealized Capital Loss Carry Forwards Tax Effected	117,900,000
U.K [Member]
Valuation Allowance, Amount	2,100,000
Operating Loss Carryforwards, Expiration Dates	no expiration
Operating Loss Carryforwards, Valuation Allowance	$ 8,100,000