Related-Party Transactions (Premiums And Losses Ceded By The Company To Affiliate) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Bermuda Re [Member]
Related Party Transaction [Line Items]
Ceded written premiums	$ 681,776	$ 544,495	$ 1,316,672	$ 1,061,178
Ceded earned premiums	620,897	593,349	1,209,771	1,132,302
Ceded losses and LAE	388,573	404,667	728,704	695,143
Everest International [Member]
Related Party Transaction [Line Items]
Ceded written premiums	45	62	(25)	31
Ceded earned premiums	46	63	(25)	39
Ceded losses and LAE	(175)	756	(618)	898
Everest Canada [Member]
Related Party Transaction [Line Items]
Assumed written premiums	13,132	16,228	25,980	26,427
Assumed earned premiums	11,884	12,675	24,737	23,129
Assumed losses and LAE	7,319	14,440	13,970	21,427
Lloyd's Syndicate [Member]
Related Party Transaction [Line Items]
Assumed written premiums	10,236	(157)	18,085	539
Assumed earned premiums	9,797	28	16,724	116
Assumed losses and LAE	4,831		8,264
Mt. Logan Re Segregated Accounts [Member]
Related Party Transaction [Line Items]
Ceded written premiums	38,703	29,450	77,882	70,381
Ceded earned premiums	50,708	39,356	84,665	74,228
Ceded losses and LAE	23,674	16,232	43,433	25,330
Assumed written premiums	3,763	3,074	6,495	6,634
Assumed earned premiums	3,763	3,074	6,495	6,634
Assumed losses and LAE