Commitments and Contingencies (Details) (USD $)	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Commitments and Contingencies [Line Items]
Recognized Gross losses from catastrophic events	$ 168,000,000	$ 26,900,000
Liability related to indemnifications	9,000,000
Pretax loss after reinsurance	107,900,000	15,600,000
Letters of credit to cover obligations or anticipated payments	5,200,000
Amount in escrow account	$ 3,000,000