Income Taxes (Schedule Of Principal Components Of Deferred Taxes) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
NOL carryover	$ 1,375,759	$ 1,266,972
Compensation	284,761	334,576
Long-term debt	89,160	134,079
Other assets	162,393	160,586
Securities valuation reserves	32,141	25,499
Intangible assets, net and goodwill	6,855	13,842
Other liabilities	40,393	57,006
Gross tax assets	1,991,462	1,992,560
Valuation allowance	(97,177)	(110,404)
Total deferred tax assets, net	1,894,285	1,882,156
Unrealized gains on investments	(153,035)	(10,406)
Amortization of intangible assets	(103,561)	(97,268)
Property and equipment	(4,151)	(866)
Other	(58,170)	(61,081)
Gross tax liability	(318,917)	(169,621)
Net deferred tax asset	$ 1,575,368	$ 1,712,535