Investments (Schedule Of Net Investment Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net Investment Income [Line Items]
Net investment income	$ 43,412	$ 39,271	$ 127,824	$ 110,294
Fixed maturity investments [Member]
Net Investment Income [Line Items]
Net investment income	38,762	31,179	110,998	96,366
Equity securities [Member]
Net Investment Income [Line Items]
Net investment income	3,711	6,110	12,876	13,718
Other invested assets - hedge funds and private equity [Member]
Net Investment Income [Line Items]
Net investment income	2,249	3,812	8,767	6,001
Other invested assets - other private securities [Member]
Net Investment Income [Line Items]
Net investment income	3,292	1,997	7,291	5,115
Cash and cash equivalents [Member]
Net Investment Income [Line Items]
Net investment income	552	302	1,562	1,319
Expenses [Member]
Net Investment Income [Line Items]
Net investment income	$ (5,154)	$ (4,129)	$ (13,670)	$ (12,225)