Income Taxes (Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Components Of Income Tax Expense Benefit Continuing Operations [Abstract]
Deferred compensation	$ 173,759	$ 161,972
Net operating loss carryforwards	48,831	50,251
Accrued expenses	65,451	37,673
Unrealized loss on investments	27,769	35,855
Depreciation	10,055	13,306
Receivable reserves	16,343	10,595
Investment and jobs creation credit		350
Total deferred tax assets	342,208	310,002
Valuation allowance	(12,738)	(7,385)
Deferred tax assets	329,470	302,617
Goodwill and other intangibles	(33,437)	(24,346)
Change in accounting method	(625)	(12,270)
Prepaid expenses	(4,211)	(3,602)
Other	(6,070)	(4,257)
Total deferred tax liabilities	(44,343)	(44,475)
Net deferred tax asset	$ 285,127	$ 258,142