Income Taxes (Deferred Tax Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Income Taxes [Abstract]
Deferred compensation	$ 161,972	$ 163,411
Net operating loss carryforwards	50,251	53,325
Accrued expenses	37,673	45,210
Unrealized gain on investments	35,855us-gaap_DeferredTaxAssetsInvestments	30,211us-gaap_DeferredTaxAssetsInvestments
Depreciation	13,306sf_DeferredTaxAssetsDepreciation	11,537sf_DeferredTaxAssetsDepreciation
Receivable reserves	10,595	6,010
Investment and jobs creation credit	350	1,627
Total deferred tax assets	310,002us-gaap_DeferredTaxAssetsGross	311,331us-gaap_DeferredTaxAssetsGross
Valuation allowance	(7,385)	(9,854)
Deferred tax assets	302,617us-gaap_DeferredTaxAssetsNet	301,477us-gaap_DeferredTaxAssetsNet
Goodwill and other intangibles	(24,346)	(25,826)
Change in accounting method	(12,270)	(21,852)
Prepaid expenses	(3,602)	(4,938)
Unrealized gain on investments	(4,257)	(5,307)
Total deferred tax liabilities	(44,475)us-gaap_DeferredTaxLiabilities	(57,923)us-gaap_DeferredTaxLiabilities
Net deferred tax asset	$ 258,142us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 243,554us-gaap_DeferredTaxAssetsLiabilitiesNet

Deferred Tax Assets, Depreciation

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Deferred Tax Liabilities, Change In Accounting Method

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from investments (excludes investments in subsidiaries and equity method investments).

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible general business tax credit carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from share-based compensation.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from accrued liabilities.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from the allowance for doubtful accounts.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances.

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Amount of deferred tax liability attributable to taxable temporary differences from intangible assets including goodwill.

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Amount of deferred tax consequences attributable to taxable temporary differences derived from prepaid expenses.

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Amount of deferred tax liability attributable to taxable temporary differences from unrealized gains on trading securities.

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