Reinsurance (Details 4) (USD $) In Thousands, unless otherwise specified	Jun. 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	$ 229,525	$ 195,806
Letters of credit	104,097	120,589
Cash deposits	105,586	83,731
Total credits	$ 439,208	$ 400,126