Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2014 InterestPlans	Sep. 30, 2013
Loss Contingencies [Line Items]
Carried interest plans	2
Carried interest rate	15.00%
Plan investment deployed amount approximately	$ 25.5	$ 23.5
Maximum
Loss Contingencies [Line Items]
Plan investment deployed amount approximately	$ 86.0

For investments which are quantified by principal amount, the principle balance held at close of period.

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

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-Name Accounting Standards Codification

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant