Reinsurance (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Effect of reinsurance transactions on our premium, loss and loss adjustment expense and policy acquisition costs
Direct written premium	$ 620,512	$ 581,571
Reinsurance assumed	126,210	138,634
Reinsurance ceded	(156,540)	(141,021)
Net written premium	590,182	579,184
Direct earned premium	637,313	616,405
Reinsurance assumed	76,023	85,272
Reinsurance ceded	(150,724)	(140,491)
Net earned premium	562,612	561,186
Direct loss and loss adjustment expense	350,727	357,512
Reinsurance assumed	41,802	39,691
Reinsurance ceded	(70,685)	(64,506)
Net loss and loss adjustment expense	321,844	332,697
Policy acquisition costs	104,645	100,286
Ceding commissions	(35,604)	(33,337)
Net policy acquisition costs	$ 69,041	$ 66,949