Related-Party Transactions (Premiums And Losses Ceded By The Company To Affiliate) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Bermuda Re [Member]
Related Party Transaction [Line Items]
Ceded written premiums		$ 634,896	$ 516,683
Ceded earned premiums		588,874	538,953
Ceded losses and LAE	[1]	340,131	290,476
Everest International [Member]
Related Party Transaction [Line Items]
Ceded written premiums		(70)	(31)
Ceded earned premiums		(71)	(24)
Ceded losses and LAE		(443)	142
Everest Canada [Member]
Related Party Transaction [Line Items]
Assumed written premiums		12,848	10,199
Assumed earned premiums		12,853	10,454
Assumed losses and LAE		6,651	6,987
Lloyd's Syndicate [Member]
Related Party Transaction [Line Items]
Assumed written premiums		7,849	696
Assumed earned premiums		6,927	88
Assumed losses and LAE		3,433	0
Mt. Logan Re Segregated Accounts [Member]
Related Party Transaction [Line Items]
Ceded written premiums		39,179	40,931
Ceded earned premiums		33,957	34,872
Ceded losses and LAE		19,759	9,098
Assumed written premiums		2,732	3,560
Assumed earned premiums		2,732	3,560
Assumed losses and LAE

[1] Ceded losses and LAE include the Mt. McKinley loss portfolio transfer that constitutes losses ceded under retroactive reinsurance and therefore, in accordance with FASB guidance, amortization of deferred gain on retroactive reinsurance is reflected in other income on the consolidated statements of operations and comprehensive income (loss). Upon the sale of Mt. McKinley, the value of the remaining deferred gain on retroactive reinsurance was included in the calculation of the realized gain on sale of subsidiary.