Agreements with Related Parties (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
[AtradiusNvMember]
Related Party Transaction [Line Items]
Net premiums written	$ 75,991	$ 80,975	$ 49,487
Net premiums earned	77,230	69,094	63,724
Losses and loss expenses and life policy benefits	32,595	40,740	58,394
Acquisition costs	33,906	22,012	20,824
Reinsurance balances receivable	5,332	21,571
Unpaid losses and loss expenses	75,173	71,929
Unearned premiums	34,836	36,744
Other net assets	14,187	12,916
[DeltaLloydMember]
Related Party Transaction [Line Items]
Net premiums earned	1,900	1,200	1,400
Losses and loss expenses and life policy benefits	800	300	500
Unpaid losses and loss expenses	$ 7,500	$ 8,900