Reinsurance (Details 4) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Amounts of letters of credit and cash deposits held by us as collateral, plus other credits available for potential offset
Payables to reinsurers	$ 201,598	$ 195,806
Letters of credit	97,357	120,589
Cash	112,105	83,731
Total credits	$ 411,060	$ 400,126