Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred Tax Assets:
Basis adjustments (primarily as a result of (i) the separation and recapitalization transactions that occurred during 2005 in connection with our initial public offering and (ii) subsequent secondary offerings)	$ 598,607	$ 739,059
Compensation and benefits	258,976	250,413
Net operating loss and tax credit carryforwards	283,198	348,433
Depreciation and amortization	950	8,169
Other	36,470us-gaap_DeferredTaxAssetsOther	58,273us-gaap_DeferredTaxAssetsOther
Gross deferred tax assets	1,178,201us-gaap_DeferredTaxAssetsGross	1,404,347us-gaap_DeferredTaxAssetsGross
Valuation allowance	(1,044,152)	(1,225,305)
Deferred tax assets (net of valuation allowance)	134,049us-gaap_DeferredTaxAssetsNet	179,042us-gaap_DeferredTaxAssetsNet
Deferred Tax Liabilities:
Depreciation and amortization	21,908	19,296
Compensation and benefits	28,035	30,042
Goodwill	15,289	15,434
Other	39,705us-gaap_DeferredTaxLiabilitiesOther	70,394us-gaap_DeferredTaxLiabilitiesOther
Deferred tax liabilities	$ 104,937us-gaap_DeferredTaxLiabilities	$ 135,166us-gaap_DeferredTaxLiabilities

Gross Deferred Tax Assets Pertaining To Basis Adjustments

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Gross deferred tax assets pertaining to depreciation and amortization.

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Gross Deferred Tax Assets Pertaining To Net Operating Loss And Tax Credit Carryforwards

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Gross Deferred Tax Liabilities Pertaining To Compensation And Benefits

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Gross deferred tax liabilities pertaining to depreciation and amortization.

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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 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 temporary differences from compensation and benefits costs.

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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 goodwill.

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