Deferred Policy Acquisition Costs (Amounts Of Policy Acquisition Costs Deferred And Amortized) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance, beginning of year	$ 465,569	$ 392,410	$ 352,756
Policy acquisition costs deferred	1,024,888	964,755	823,840
Amortization of policy acquisition costs	(1,009,303)	(894,353)	(782,221)
Foreign currency movements	(6,641)	2,757	(1,965)
Deferred policy acquisition costs	$ 474,513	$ 465,569	$ 392,410