Incentive Plans - Summary of Funds Interests and Other Similar Deferred Compensation Arrangements (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Prepaid Compensation Assets, Beginning Balance	$ 17,783
Prepaid Compensation Assets, Granted	64,679
Prepaid Compensation Assets, Settled
Prepaid Compensation Assets, Forfeited	(1,603)
Prepaid Compensation Assets, Amortization	(33,476)
Prepaid Compensation Assets, Change in fair value of underlying investments
Prepaid Compensation Assets, Adjustment for estimated forfeitures
Prepaid Compensation Assets, Other	62
Prepaid Compensation Assets, Ending Balance	47,445
Compensation Liability, Beginning Balance	29,900
Compensation Liability, Granted	64,679
Compensation Liability, Settled	(10,646)
Compensation Liability, Forfeited	(1,711)
Compensation Liability, Amortization
Compensation Liability, Change in fair value of underlying investments	7,557
Compensation Liability, Adjustment for estimated forfeitures	7,841
Compensation Liability, Other	(27)
Compensation Liability, Ending Balance	$ 97,593

Derivative Liability Adjustment To Forfeiture

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- Definition

Derivative liability, amortization.

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No definition available.

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Derivative liability, change in fair value.

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No definition available.

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Derivative liability, foreign currency translation and other adjustments.

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No definition available.

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- Definition

Derivative liability forfeited.

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No definition available.

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Derivative liability, granted.

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No definition available.

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- Definition

Derivative Liability, Vested

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No definition available.

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- Definition

Prepaid compensation asset.

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No definition available.

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- Definition

Prepaid Compensation Asset Adjustment To Forfeiture

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Prepaid compensation asset, change in fair value.

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Prepaid compensation asset, foreign currency translation and other adjustments.

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Prepaid compensation asset forfeited.

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Prepaid compensation asset, granted.

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Prepaid compensation asset, settled.

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No definition available.

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The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives.

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-Publisher FASB

-Name Accounting Standards Codification

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- Definition

Fair value of derivative liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 205G

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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